BACKGROUND While existing literature on ischiofemoral impingement syndrome(IFI)predominantly emphasizes surgical interventions or generalized physical therapy approaches,there remains a paucity of evidence regarding s...BACKGROUND While existing literature on ischiofemoral impingement syndrome(IFI)predominantly emphasizes surgical interventions or generalized physical therapy approaches,there remains a paucity of evidence regarding structured,multimodal rehabilitation programs targeting biomechanical deficits in IFI.This case report evaluates the efficacy of a multimodal rehabilitation program addressing a critical gap in conservative management strategies.CASE SUMMARY The patient underwent comprehensive physical and clinical examination,including hip X-ray and magnetic resonance imaging investigations.The patient completed the Musculoskeletal Health Questionnaire(MSK-HQ)and numerical pain rating scale(NPRS).The patient underwent a two-month tailored structured physical therapy intervention and repeated the same assessment afterwards.The patient's substantial reduction in pain,reflected by a significant decrease in the patient’s NPRS score from 9 to 3 points,signifies a positive clinical response.This outcome,coupled with the significant improvement in the patient's health-related quality of life according to the MSK-HQ score,which increased from 12 to 48 points,underscores the success of our research.CONCLUSION The study highlights the importance of a comprehensive approach to diagnosing and managing IFI,combining clinical assessment with imaging and implementing a multimodal rehabilitation program for optimal outcomes.展开更多
This commentary evaluates the case report by Mohammed et al on conservative management of ischiofemoral impingement through a multimodal physical therapy program integrating in-person sessions,telerehabilitation,dry n...This commentary evaluates the case report by Mohammed et al on conservative management of ischiofemoral impingement through a multimodal physical therapy program integrating in-person sessions,telerehabilitation,dry needling,and kinesiology taping.The study demonstrated significant pain reduction and functional improvement,highlighting the feasibility of hybrid care models.However,limitations include short-term follow-up,lack of post-treatment imaging,and single-case design restricting generalizability.Future research should prioritize longitudinal studies,anatomical correlation via imaging,and randomized trials to validate efficacy across diverse populations.While the framework offers promising clinical utility,further investigation is critical to optimize protocols and elucidate biomechanical mechanisms underlying symptom resolution.展开更多
This numerical simulation investigates the two⁃phase flow under the condition of supercooled large droplets impinging on the aircraft surface.Based on Eulerian framework,a method for calculating supercooled water drop...This numerical simulation investigates the two⁃phase flow under the condition of supercooled large droplets impinging on the aircraft surface.Based on Eulerian framework,a method for calculating supercooled water droplet impingement characteristics is established.Then,considering the deformation and breaking effects during the movement,this method is extended to calculate the impingement characteristics of supercooled large droplets,as well as the bouncing and splashing effects during impingement.The impingement characteristics of supercooled large droplets is then investigated by this method.The results demonstrate that the deformation and breaking effects of supercooled large droplets have negligible influence on the impingement characteristics under the experimental conditions of this paper.In addition,the results of the impingement range and collection efficiency decrease when considering the bouncing and splashing effects.The bouncing effect mainly affects the mass loss near the impingement limits,while the splashing effect influences the result around the stagnation point.This investigation is beneficial for the analysis of aircraft icing and the design of anti⁃icing system with supercooled large droplet conditions.展开更多
To improve the controllability of the wall-wetting process after the fuel spray-wall impingement in internal combustion engines,the methods of laser etching,chemical etching and surface free energy modification are us...To improve the controllability of the wall-wetting process after the fuel spray-wall impingement in internal combustion engines,the methods of laser etching,chemical etching and surface free energy modification are used to prepare biomimetic structured surfaces with different wettability.The impingement processes of diesel and n-butanol sprays on the walls under different conditions are experimentally investigated.As the surface oleophilicity increases,the spreading radius of wall-impinging sprays decreases.At about 5 s after the fuel injections,the fuel spray droplets hit the walls for the first time,and the secondary breakup and rebound occur.The mixture concentrations of different fuels hitting the various walls reach the peak value.Under a higher surface temperature,the peak value of the mixture concentration is mainly related to the heat flux to the fuel droplets in different boiling regimes from the metal surfaces.The concentration of the air–fuel mixture in the near wall region increases with increasing surface oleophilicity,increasing wall temperature and decreasing ambient pressure.Compared with diesel,n-butanol presents a higher air–fuel mixture concentration in the near wall region.展开更多
Three-dimensional numerical simulation is carried out to investigate the flow and heat transfer characteristics of impingement/effusion cooling systems. The impingement/effusion holes are arranged on two parallel perf...Three-dimensional numerical simulation is carried out to investigate the flow and heat transfer characteristics of impingement/effusion cooling systems. The impingement/effusion holes are arranged on two parallel perforated plates respectively in a staggered manner. Every effusion hole has an inclined angle of 30° with respect to the surface. The two parallel plates are spaced three times the diameter of the effusion hole. The ratio of center-to-center spacing of adjacent holes to the diameter of the effusion hole is set to be 3.0, 4.0 and 5.0 respectively. The flow field, temperature field and wall film cooling effectiveness are calculated for different blowing ratios ranging from 0.5 to 1.5. In general, the wall cooling effectiveness increases as the center-to-center spacing of adjacent holes decreases or the blowing ratio increases.展开更多
Experimental study of the local and average heat transfer characteristics of a single round jet impinging on the concave surfaces was conducted in this work to gain in-depth knowledge of the curvature effects.The expe...Experimental study of the local and average heat transfer characteristics of a single round jet impinging on the concave surfaces was conducted in this work to gain in-depth knowledge of the curvature effects.The experiments were conducted by employing a piccolo tube with one single jet hole over a wide range of parameters：jet Reynolds number from 27000 to 130000,relative nozzle to surface distance from 3.3 to 30,and relative surface curvature from 0.005 to 0.030.Experimental results indicate that the surface curvature has opposite effects on heat transfer characteristics.On one hand,an increase of relative nozzle to surface distance（increasing jet diameter in fact）enhances the average heat transfer around the surface for the same curved surface.On the other hand,the average Nusselt number decreases as relative nozzle to surface distance increases for a fixed jet diameter.Finally,experimental data-based correlations of the average Nusselt number over the curved surface were obtained with consideration of surface curvature effect.This work contributes to a better understanding of the curvature effects on heat transfer of a round jet impingement on concave surfaces,which is of high importance to the design of the aircraft anti-icing system.展开更多
To address the curvature effect on single-row chevron-nozzle jet impingement heat transfer on concave surface,a series of experiments are conducted in the present investigation.Four concave surfaces including one semi...To address the curvature effect on single-row chevron-nozzle jet impingement heat transfer on concave surface,a series of experiments are conducted in the present investigation.Four concave surfaces including one semi-cylindrical concave surface and three parabolic concave surfaces with different width-to-depth ratios are tested under three typical Reynolds numbers(Re=5000,10000 and 15000)and several dimensionless nozzle-to-surface distances ranging from 1 to 8.The results show that the concave curvature has a clear impact on chevron-nozzle jet impingement heat transfer,tightly dependent on jet Reynolds number and impinging distance.In general,the semicylindrical concave surface produces the highest longitudinally-averaged Nusselt number at the leading line of concave surface.Under a low jet Reynolds number,the parabolic concave surface with a highly curved curvature produces higher longitudinally-averaged Nusselt number at the leading line and more uniform longitudinally-averaged Nusselt number distribution along the curvilinear direction.However,the longitudinally-averaged Nusselt number at the leading line of concave surface is the lowest for the highly curved surface under a high jet Reynolds number and large impinging distance.In comparison with the round-nozzle,chevron nozzle plays a more significant role on improving jet impingement heat transfer at small impinging distances.展开更多
Extensive experimental studies on the heat transfer characteristics of two rows of aligned jet holes impinging on a concave surface in a wing leading edge were conducted, where50000 Rej 90000, 1.74 H/d 27.5, 66° ...Extensive experimental studies on the heat transfer characteristics of two rows of aligned jet holes impinging on a concave surface in a wing leading edge were conducted, where50000 Rej 90000, 1.74 H/d 27.5, 66° a 90°, and 13.2 r/d 42.03. The finding was that the heat transfer performance at the jet-impingement stagnation point with two rows of aligned jet holes was the same as that with a single row of jet holes or the middle row of three-row configurations when the circumferential angle of the two jet holes was larger than 30°. The attenuation coefficient distribution of the jet impingement heat transfer in the chordwise direction was so complicated that two zones were divided for a better analysis. It indicated that： the attenuation coefficient curve in the jet impingement zone exhibited an approximate upside-down bell shape with double peaks and a single valley; the attenuation coefficient curve in the non-jet impingement zone was like a half-bell shape, which was similar to that with three rows of aligned jet holes; the factors,including Rej, H/d and r/d, affected the attenuation coefficient value at the valley significantly.When r/d was increased from 30.75 to 42.03, the attenuation rates of attenuation coefficient increased only by 1.8%. Consequently, experimental data-based correlation equations of the Nusselt number for the heat transfer at the jet-impingement stagnation point and the distributionof the attenuation coefficient in the chordwise direction were acquired, which play an important role in designing the wing leading edge anti-icing system with two rows of aligned jet holes.展开更多
Posterior ankle impingement syndrome(PAIS) is a common injury in athletes engaging in repetitive plantarflexion, particularly ballet dancers and soccer players. Despite the increase in popularity of the posterior twop...Posterior ankle impingement syndrome(PAIS) is a common injury in athletes engaging in repetitive plantarflexion, particularly ballet dancers and soccer players. Despite the increase in popularity of the posterior twoportal hindfoot approach, concerns with the technique remain, including; the technical difficulty, relatively steep learning curve, and difficulty performing simultaneous anterior ankle arthroscopy. The purpose of the current literature review is to provide comprehensive knowledge about PAIS, and to describe a systematic four-stage approach of the posterior two-portal arthroscopy. The etiology, clinical presentation, diagnostic strategies are first introduced followed by options in conservative and surgical management. A detailed systematic approach to posterior hindfoot arthroscopy is then described. This technique allows for systematic review of the anatomic structures and treatment of the bony and/or soft tissue lesions in four regions of interest in the hindfoot(superolateral, superomedial, inferomedial, and inferolateral). The review then discusses biological adjuncts and postoperative rehabilitation and ends with a discussion on the most recent clinical outcomes after posterior hindfoot arthroscopy for PAIS. Although clinical evidence suggests high success rates following posterior hindfoot arthroscopy in the short- and mid-term it may be limited in the pathology that can be addressed due to the technical skills required, but the systematic four-stage approach of the posterior two-portal arthroscopy may improve upon this problem.展开更多
At jet pressures ranging from 80 to 120 MPa, submerged water jets are investigated by numerical simulation and experiment. Numerical simulation enables a systematic analysis of major flow parameters such as jet veloci...At jet pressures ranging from 80 to 120 MPa, submerged water jets are investigated by numerical simulation and experiment. Numerical simulation enables a systematic analysis of major flow parameters such as jet velocity, turbulent kinetic energy as well as void fraction of cavitation. Experiments facilitate an objective assessment of surface morphology, micro hardness and surface roughness of the impinged samples. A comparison is implemented between submerged and non-submerged water jets. The results show that submerged water jet is characterized by low velocity magnitudes relative to non-submerged water jet at the same jet pressure. Shear effect serves as a key factor underlying the inception of cavitation in submerged water jet stream. Predicted annular shape of cavity zone is substantiated by local height distributions associated with experimentally obtained footprints. As jet pressure increases, joint contribution of jet kinetic energy and cavitation is demonstrated. While for non-submerged water jet, impingement force stems exclusively from flow velocity.展开更多
An enlarged model of trapezoidal duct near the leading-edge in the blade is built up. The effects of impingement jets, swirl flow, cross flow and effusion flow are considered. Experiments are performed to measure flow...An enlarged model of trapezoidal duct near the leading-edge in the blade is built up. The effects of impingement jets, swirl flow, cross flow and effusion flow are considered. Experiments are performed to measure flow fields in this confined passage and exit holes on one of its side walls. Cross flow and effusion flow are induced in the channel by the outflow of side exit hole （SEH） and film cooling hole （FCH）, which are oriented on one end wall and bottom wall of the passage. Detailed flow structures are measured for two impingement angles of 35° and 45° with 6 combinations of outflow ratios. Results show that the small jets impinge the target wall effectively while the large jets contribute to inducing and impelling a strong counter-clockwise vortex in the upper part of the passage. Cross flow plays a dominate role for the flow structures in the passage and exit holes. It deflects jets, enhances swirl and deteriorates side exit conditions. Impingement angle is another significant factor for the flow characteristics. Its effect reveals more evidently with cross flow. Within the present test conditions, the mass flow rates and outflow positions of FCHs have no distinct effect on the main flow structures.展开更多
Femoroacetabular impingement(FAI)is an increasingly recognized condition,which is believed to contribute to degenerative changes of the hip.This correlation has led to a great deal of interested in diagnosis and treat...Femoroacetabular impingement(FAI)is an increasingly recognized condition,which is believed to contribute to degenerative changes of the hip.This correlation has led to a great deal of interested in diagnosis and treatment of FAI.FAI can be divided into two groups:cam and pincer type impingement.FAI can lead to chondral and labral pathologies,that if left untreated,can progress rapidly to osteoarthritis.The diagnosis of FAI involves a detailed history,physical exam,and radiographs of the pelvis.Surgical treatment is indicated in anatomic variants known to cause FAI.The primary goal of surgical treatment is to increase joint clearance and decrease destructive forces being transmitted through the joint.Treatment has been evolving rapidly over the past decade and includes three primary techniques:open surgical dislocation,mini-open,and arthroscopic surgery.Open surgical dislocation is a technique for dislocating the femoral head from the acetabulum with a low risk of avascular necrosis in orderto reshape the neck or acetabular rim to improve joint clearance.Mini-open treatment is performed using the distal portion of an anterior approach to the hip to visualize and to correct acetabular and femoral head and neck junction deformities.This does not involve frank dislocation.Recently,arthroscopic treatment has gained popularity.This however does have a steep learning curve and is best done by an experienced surgeon.Short-to mid-term results have shown relatively equal success with all techniques in patients with no or only mild evidence of degenerative changes.Additionally,all techniques have demonstrated low rates of complications.展开更多
The multiple jets impingement heat transfer is widely applied in the wing anti-icing system.It is challenging to apply the similarity criterion to carry out the anti-icing experiments due to the complex flow and heat ...The multiple jets impingement heat transfer is widely applied in the wing anti-icing system.It is challenging to apply the similarity criterion to carry out the anti-icing experiments due to the complex flow and heat transfer behavior.In the present study,the full-scale slat model is used to carry out anti-icing experimental researches in a 2 m×3 m icing wind tunnel of China Aerodynamics Research and Development Center.The effects of icing parameters Liquid Water Content(LWC)and Median Volume Diameter(MVD)and hot air parameters(mass flow rate and temperature)on the thermal performance of an inner-liner anti-icing system with jets impingement heat transfer are studied.The effects of the experimental parameters are analyzed in detail by combining impingement and evaporation heat transfer mechanisms.The impingement hot air mass flow rate dramatically affects the heat transfer performance of the impingement stagnation region within the range of the experimental parameters.The temperature of impingement hot air and that of wing skin are approximately linear correlated.The experimental results show the effects of LWC and MVD on water film formation and runback ice accretion.The formation of water film is analyzed by an analytical method based on the wing skin temperature difference of dry and wet air conditions.展开更多
The aim of this study is to examine the effects of local curvature and elastic wall effects of an isothermal hot wall for the purpose of jet impingement cooling performance.Finite element method was used with ALE.Diff...The aim of this study is to examine the effects of local curvature and elastic wall effects of an isothermal hot wall for the purpose of jet impingement cooling performance.Finite element method was used with ALE.Different important parametric effects such as Re number(between 100 and 700),Ha number(between 0 and 20),elasticity(between 104 and 109),curvature of the surface(elliptic,radius ratio between 1 and 0.25) and nanoparticle volume fraction(between 0 and 0.05) on the cooling performance were investigated numerically.The results showed that the average Nu number enhances for higher Hartmann number,higher values of elastic modulus of partly flexible wall and higher nanoparticle volume fraction.When the magnetic field is imposed at the highest strength,there is an increase of3.85% in the average Nu for the curved elastic wall whereas it is 89.22% for the hot part above it,which is due to the vortex suppression effects.Nanoparticle inclusion in the base fluid improves the heat transfer rate by about 27.6% in the absence of magnetic field whereas it is 20.5% under the effects of magnetic field at Ha=20.Curvature effects become important for higher Re numbers and at Re=700,there is 14.11% variation in the average Nu between the cases with the lowest and highest radius ratio.The elastic wall effects on the heat transfer are reduced with the increased curvature of the bottom wall.展开更多
Heat transfer characteristics in a narrow confined channel with discrete impingement cooling were investigated using thermal infrared camera. Detailed heat transfer distributions and comparisons on three surfaces with...Heat transfer characteristics in a narrow confined channel with discrete impingement cooling were investigated using thermal infrared camera. Detailed heat transfer distributions and comparisons on three surfaces with three impact diameters were experimentally studied in the range of Reynolds number of 3000 to 30000. The experimental results indicated that the strong impingement jet leaded to a high strength heat transfer zone in the ΔX=±2.5D;range of the impact center,which was 1.3–2.5 times of the average heat transfer value of the impingement wall. With the same coolant mass flow rate, small diameter case had lower heat transfer coefficient on both inner wall and outside wall, while the impingement wall was insensitive to the impact diameter. The surface averaged Nusselt number of inner wall was only 43%–57% of impingement wall, while the outside wall can reach up to 80%–90%. The larger the diameter, the higher heat transfer enhancement and the smaller the channel flow resistance was observed in term of Reynolds number. The surface averaged Nusselt numbers were developed as the function of Reynolds number and the impingement height-to-diameter for further engineering applications.展开更多
As a novel supersonic jet technology,preheating shrouded supersonic jet was developed to deliver oxygen into molten bath efficiently and affordably.However,there has been limited research on the jet behavior and impin...As a novel supersonic jet technology,preheating shrouded supersonic jet was developed to deliver oxygen into molten bath efficiently and affordably.However,there has been limited research on the jet behavior and impingement characteristics of preheating shrouded supersonic jets.Computational fluid dynamics（CFD）models were established to investigate the effects of main and shrouding gas temperatures on the characteristics of flow field and impingement of shrouded supersonic jet.The preheating shrouded supersonic jet behavior was simulated and measured by numerical simulation and jet measurement experiment respectively.The influence of preheating shrouded supersonic jet on gas jet penetration and fluid flow in liquid bath was calculated by the CFD model which was validated against water model experiments.The results show that the uptrend of the potential core length of shrouded supersonic jet would be accelerated with increasing the main and shrouding gas temperatures.Also,preheating supersonic jets demonstrated significant advantages in penetrating and stirring the liquid bath.展开更多
AIM: To investigate the association between sports hernias and femoroacetabular impingement(FAI) in athletes.METHODS: Pub Med, MEDLINE, CINAHL, Embase, Cochrane Controlled Trials Register, and Google Scholar databases...AIM: To investigate the association between sports hernias and femoroacetabular impingement(FAI) in athletes.METHODS: Pub Med, MEDLINE, CINAHL, Embase, Cochrane Controlled Trials Register, and Google Scholar databases were electronically searched for articles relating to sports hernia, athletic pubalgia, groin pain, long-standing adductor-related groin pain, Gilmore groin, adductor pain syndrome, and FAI. The initial search identified 196 studies, of which only articles reporting on the association of sports hernia and FAI or laparoscopic treatment of sports hernia were selected for systematic review. Finally, 24 studies were reviewed to evaluate the prevalence of FAI in cases of sports hernia and examine treatment outcomes and evidence for a common underlying pathogenic mechanism.RESULTS: FAI has been reported in as few as 12% to as high as 94% of patients with sports hernias, athletic pubalgia or adductor-related groin pain. Cam-type impingement is proposed to lead to increased symphyseal motion with overload on the surrounding extra-articular structures and muscle, which can result in the development of sports hernia and athletic pubalgia. Laparoscopic repair of sports hernias, via either the transabdominal preperitoneal or extraperitoneal approach, has a high success rate and earlier recovery of full sports activity compared to open surgery or conservative treatment. For patients with FAI and sports hernia, the surgical management of both pathologies is more effective than sports pubalgia treatment or hip arthroscopy alone(89% vs 33% of cases). As sports hernias and FAI are typically treated by general and orthopedic surgeons, respectively, a multidisciplinary approach for diagnosis and treatment is recommended for optimal treatment of patients with these injuries.CONCLUSION: The restriction in range of motion due to FAI likely contributes to sports hernias; therefore, surgical treatment of both pathologies represents an optimal therapy.展开更多
One of the most common pathologic processes seen in overhead throwing athletes is posterior shoulderpain resulting from internal impingement. "Internal impingement" is a term used to describe a constellation...One of the most common pathologic processes seen in overhead throwing athletes is posterior shoulderpain resulting from internal impingement. "Internal impingement" is a term used to describe a constellation of symptoms which result from the greater tuberosity of the humerus and the articular surface of the rotator cuff abutting the posterosuperior glenoid when the shoulder is in an abducted and externally rotated position. The pathophysiology in symptomatic internal impingement is multifactorial,involving physiologic shoulder remodeling,posterior capsular contracture,and scapular dyskinesis. Throwers with internal impingement may complain of shoulder stiffness or the need for a prolonged warm-up,decline in performance,or posterior shoulder pain. On physical examination,patients will demonstrate limited internal rotation and posterior shoulder pain with a posterior impingement test. Common imaging findings include the classic "Bennett lesion" on radiographs,as well as articular-sided partial rotator cuff tears and concomitant SLAP lesions. Mainstays of treatment include intense non-operative management focusing on rest and stretching protocols focusing on the posterior capsule. Operative management is variable depending on the exact pathology,but largely consists of rotator cuff debridement. Outcomes of operative treatment have been mixed,therefore intense non-operative treatment should remain the focus of treatment.展开更多
Experimental investigation is conducted to investigate the flow and heat transfer performances of jet impingement cooling inside a semi-confined smooth channel.Effects of jet Reynolds number(varied from 10 000to 45000...Experimental investigation is conducted to investigate the flow and heat transfer performances of jet impingement cooling inside a semi-confined smooth channel.Effects of jet Reynolds number(varied from 10 000to 45000),orifice-to-target spacing(zn=1d—4d)and jet-to-jet pitches(xn=3d—5d,yn=3d—5d)on the convective heat transfer coefficient and discharge coefficient are revealed.For a single-row jets normal impingement,the impingement heat transfer is enhanced with the increase of impingement Reynolds number or the decrease of spanwise jet-to-jet pitch.The highest local heat transfer is achieved when zn/dis 2.For the double-row jets normal impingement,the laterally-averaged Nusselt number distributions in the vicinity of the first row jets impinging stagnation do not fit well with the single-row case.The highest local heat transfer is obtained when zn/dis 1.A smaller jetto-jet pitch generally results in a lower discharge coefficient.The discharge coefficient in the double-row case is decreased relative to the single-row case at the same impingement Reynolds number.展开更多
The 3-D numerical computation of the flow and temperature fields for jet array impingement with initial crossflow investigates the effects of the jet-to-surface spacing, the impinging hole arrangement and the jet-to-c...The 3-D numerical computation of the flow and temperature fields for jet array impingement with initial crossflow investigates the effects of the jet-to-surface spacing, the impinging hole arrangement and the jet-to-crossflow mass flux ratio on heat transfer characteristics. The study shows that: (1) under the different jet-to-surface spacing, the impingement cooling with inline arrangement is better than that with staggered arrangement for a given jet-to-crossflow mass flux ratio;( 2 ) the value of jet-to-surface spacing impacts a complicated effect on the flow and heat transfer for jet array impingement; (3) as the ratio of crossflow-to-jet mass flux ratio increases, the cooling effectiveness on monotonous decrease for both inline and staggered arrangements at the same jet-to-surface spacing.展开更多
文摘BACKGROUND While existing literature on ischiofemoral impingement syndrome(IFI)predominantly emphasizes surgical interventions or generalized physical therapy approaches,there remains a paucity of evidence regarding structured,multimodal rehabilitation programs targeting biomechanical deficits in IFI.This case report evaluates the efficacy of a multimodal rehabilitation program addressing a critical gap in conservative management strategies.CASE SUMMARY The patient underwent comprehensive physical and clinical examination,including hip X-ray and magnetic resonance imaging investigations.The patient completed the Musculoskeletal Health Questionnaire(MSK-HQ)and numerical pain rating scale(NPRS).The patient underwent a two-month tailored structured physical therapy intervention and repeated the same assessment afterwards.The patient's substantial reduction in pain,reflected by a significant decrease in the patient’s NPRS score from 9 to 3 points,signifies a positive clinical response.This outcome,coupled with the significant improvement in the patient's health-related quality of life according to the MSK-HQ score,which increased from 12 to 48 points,underscores the success of our research.CONCLUSION The study highlights the importance of a comprehensive approach to diagnosing and managing IFI,combining clinical assessment with imaging and implementing a multimodal rehabilitation program for optimal outcomes.
文摘This commentary evaluates the case report by Mohammed et al on conservative management of ischiofemoral impingement through a multimodal physical therapy program integrating in-person sessions,telerehabilitation,dry needling,and kinesiology taping.The study demonstrated significant pain reduction and functional improvement,highlighting the feasibility of hybrid care models.However,limitations include short-term follow-up,lack of post-treatment imaging,and single-case design restricting generalizability.Future research should prioritize longitudinal studies,anatomical correlation via imaging,and randomized trials to validate efficacy across diverse populations.While the framework offers promising clinical utility,further investigation is critical to optimize protocols and elucidate biomechanical mechanisms underlying symptom resolution.
基金supported in part by the National Natural Science Foundation of China(No.51806008)the Open Fund of Key Laboratory of Rotor Aerodynamics Key Laboratory(No.RAL202104-2)。
文摘This numerical simulation investigates the two⁃phase flow under the condition of supercooled large droplets impinging on the aircraft surface.Based on Eulerian framework,a method for calculating supercooled water droplet impingement characteristics is established.Then,considering the deformation and breaking effects during the movement,this method is extended to calculate the impingement characteristics of supercooled large droplets,as well as the bouncing and splashing effects during impingement.The impingement characteristics of supercooled large droplets is then investigated by this method.The results demonstrate that the deformation and breaking effects of supercooled large droplets have negligible influence on the impingement characteristics under the experimental conditions of this paper.In addition,the results of the impingement range and collection efficiency decrease when considering the bouncing and splashing effects.The bouncing effect mainly affects the mass loss near the impingement limits,while the splashing effect influences the result around the stagnation point.This investigation is beneficial for the analysis of aircraft icing and the design of anti⁃icing system with supercooled large droplet conditions.
基金the financial support from the Natural Science Foundation of Jilin Province(Project code:20220101212JC)Jilin Province Specific Project of Industrial Technology Research&Development(Project code:2020C025-2)+2 种基金Free Exploration Project of Changsha Automotive Innovation Research Institute of Jilin University(Project code:CAIRIZT20220202)2021"Interdisciplinary Integration and Innovation"Project of Jilin University(Project code:XJRCYB07)Horizon 2020 MSCA(Project code:H2020-MSCA-RISE-778104-ThermaSMART).
文摘To improve the controllability of the wall-wetting process after the fuel spray-wall impingement in internal combustion engines,the methods of laser etching,chemical etching and surface free energy modification are used to prepare biomimetic structured surfaces with different wettability.The impingement processes of diesel and n-butanol sprays on the walls under different conditions are experimentally investigated.As the surface oleophilicity increases,the spreading radius of wall-impinging sprays decreases.At about 5 s after the fuel injections,the fuel spray droplets hit the walls for the first time,and the secondary breakup and rebound occur.The mixture concentrations of different fuels hitting the various walls reach the peak value.Under a higher surface temperature,the peak value of the mixture concentration is mainly related to the heat flux to the fuel droplets in different boiling regimes from the metal surfaces.The concentration of the air–fuel mixture in the near wall region increases with increasing surface oleophilicity,increasing wall temperature and decreasing ambient pressure.Compared with diesel,n-butanol presents a higher air–fuel mixture concentration in the near wall region.
基金National Natural Science Foundation of China (50876041)Aeronautical Science Foundation of China (2008ZB2014)
文摘Three-dimensional numerical simulation is carried out to investigate the flow and heat transfer characteristics of impingement/effusion cooling systems. The impingement/effusion holes are arranged on two parallel perforated plates respectively in a staggered manner. Every effusion hole has an inclined angle of 30° with respect to the surface. The two parallel plates are spaced three times the diameter of the effusion hole. The ratio of center-to-center spacing of adjacent holes to the diameter of the effusion hole is set to be 3.0, 4.0 and 5.0 respectively. The flow field, temperature field and wall film cooling effectiveness are calculated for different blowing ratios ranging from 0.5 to 1.5. In general, the wall cooling effectiveness increases as the center-to-center spacing of adjacent holes decreases or the blowing ratio increases.
基金supported by the National Natural Science Foundation of China(No.51206008)the EU Marie Curie Actions-International Incoming Fellowships(No.FP7PEOPLE-2013-IIF-626576)
文摘Experimental study of the local and average heat transfer characteristics of a single round jet impinging on the concave surfaces was conducted in this work to gain in-depth knowledge of the curvature effects.The experiments were conducted by employing a piccolo tube with one single jet hole over a wide range of parameters：jet Reynolds number from 27000 to 130000,relative nozzle to surface distance from 3.3 to 30,and relative surface curvature from 0.005 to 0.030.Experimental results indicate that the surface curvature has opposite effects on heat transfer characteristics.On one hand,an increase of relative nozzle to surface distance（increasing jet diameter in fact）enhances the average heat transfer around the surface for the same curved surface.On the other hand,the average Nusselt number decreases as relative nozzle to surface distance increases for a fixed jet diameter.Finally,experimental data-based correlations of the average Nusselt number over the curved surface were obtained with consideration of surface curvature effect.This work contributes to a better understanding of the curvature effects on heat transfer of a round jet impingement on concave surfaces,which is of high importance to the design of the aircraft anti-icing system.
基金the financial supports for this project from the National Natural Science Foundation of China(No.51776097)the Open Fund of Jiangsu Province Key Laboratory of Aerospace Power System(No.APS20A7002)the Postgraduate Research and Practice Innovation Project of Jiangsu Province(No.KYCX17 0280)
文摘To address the curvature effect on single-row chevron-nozzle jet impingement heat transfer on concave surface,a series of experiments are conducted in the present investigation.Four concave surfaces including one semi-cylindrical concave surface and three parabolic concave surfaces with different width-to-depth ratios are tested under three typical Reynolds numbers(Re=5000,10000 and 15000)and several dimensionless nozzle-to-surface distances ranging from 1 to 8.The results show that the concave curvature has a clear impact on chevron-nozzle jet impingement heat transfer,tightly dependent on jet Reynolds number and impinging distance.In general,the semicylindrical concave surface produces the highest longitudinally-averaged Nusselt number at the leading line of concave surface.Under a low jet Reynolds number,the parabolic concave surface with a highly curved curvature produces higher longitudinally-averaged Nusselt number at the leading line and more uniform longitudinally-averaged Nusselt number distribution along the curvilinear direction.However,the longitudinally-averaged Nusselt number at the leading line of concave surface is the lowest for the highly curved surface under a high jet Reynolds number and large impinging distance.In comparison with the round-nozzle,chevron nozzle plays a more significant role on improving jet impingement heat transfer at small impinging distances.
基金supported by the National Natural Science Foundation of China (No. 51206008)
文摘Extensive experimental studies on the heat transfer characteristics of two rows of aligned jet holes impinging on a concave surface in a wing leading edge were conducted, where50000 Rej 90000, 1.74 H/d 27.5, 66° a 90°, and 13.2 r/d 42.03. The finding was that the heat transfer performance at the jet-impingement stagnation point with two rows of aligned jet holes was the same as that with a single row of jet holes or the middle row of three-row configurations when the circumferential angle of the two jet holes was larger than 30°. The attenuation coefficient distribution of the jet impingement heat transfer in the chordwise direction was so complicated that two zones were divided for a better analysis. It indicated that： the attenuation coefficient curve in the jet impingement zone exhibited an approximate upside-down bell shape with double peaks and a single valley; the attenuation coefficient curve in the non-jet impingement zone was like a half-bell shape, which was similar to that with three rows of aligned jet holes; the factors,including Rej, H/d and r/d, affected the attenuation coefficient value at the valley significantly.When r/d was increased from 30.75 to 42.03, the attenuation rates of attenuation coefficient increased only by 1.8%. Consequently, experimental data-based correlation equations of the Nusselt number for the heat transfer at the jet-impingement stagnation point and the distributionof the attenuation coefficient in the chordwise direction were acquired, which play an important role in designing the wing leading edge anti-icing system with two rows of aligned jet holes.
文摘Posterior ankle impingement syndrome(PAIS) is a common injury in athletes engaging in repetitive plantarflexion, particularly ballet dancers and soccer players. Despite the increase in popularity of the posterior twoportal hindfoot approach, concerns with the technique remain, including; the technical difficulty, relatively steep learning curve, and difficulty performing simultaneous anterior ankle arthroscopy. The purpose of the current literature review is to provide comprehensive knowledge about PAIS, and to describe a systematic four-stage approach of the posterior two-portal arthroscopy. The etiology, clinical presentation, diagnostic strategies are first introduced followed by options in conservative and surgical management. A detailed systematic approach to posterior hindfoot arthroscopy is then described. This technique allows for systematic review of the anatomic structures and treatment of the bony and/or soft tissue lesions in four regions of interest in the hindfoot(superolateral, superomedial, inferomedial, and inferolateral). The review then discusses biological adjuncts and postoperative rehabilitation and ends with a discussion on the most recent clinical outcomes after posterior hindfoot arthroscopy for PAIS. Although clinical evidence suggests high success rates following posterior hindfoot arthroscopy in the short- and mid-term it may be limited in the pathology that can be addressed due to the technical skills required, but the systematic four-stage approach of the posterior two-portal arthroscopy may improve upon this problem.
基金Projects(51205171,51376081)supported by the National Natural Science Foundation of ChinaProject(1201026B)supported by the Postdoctoral Science Foundation of Jiangsu Province,China
文摘At jet pressures ranging from 80 to 120 MPa, submerged water jets are investigated by numerical simulation and experiment. Numerical simulation enables a systematic analysis of major flow parameters such as jet velocity, turbulent kinetic energy as well as void fraction of cavitation. Experiments facilitate an objective assessment of surface morphology, micro hardness and surface roughness of the impinged samples. A comparison is implemented between submerged and non-submerged water jets. The results show that submerged water jet is characterized by low velocity magnitudes relative to non-submerged water jet at the same jet pressure. Shear effect serves as a key factor underlying the inception of cavitation in submerged water jet stream. Predicted annular shape of cavity zone is substantiated by local height distributions associated with experimentally obtained footprints. As jet pressure increases, joint contribution of jet kinetic energy and cavitation is demonstrated. While for non-submerged water jet, impingement force stems exclusively from flow velocity.
基金Chinese Postdoctoral Science Foundation (20090461472)
文摘An enlarged model of trapezoidal duct near the leading-edge in the blade is built up. The effects of impingement jets, swirl flow, cross flow and effusion flow are considered. Experiments are performed to measure flow fields in this confined passage and exit holes on one of its side walls. Cross flow and effusion flow are induced in the channel by the outflow of side exit hole （SEH） and film cooling hole （FCH）, which are oriented on one end wall and bottom wall of the passage. Detailed flow structures are measured for two impingement angles of 35° and 45° with 6 combinations of outflow ratios. Results show that the small jets impinge the target wall effectively while the large jets contribute to inducing and impelling a strong counter-clockwise vortex in the upper part of the passage. Cross flow plays a dominate role for the flow structures in the passage and exit holes. It deflects jets, enhances swirl and deteriorates side exit conditions. Impingement angle is another significant factor for the flow characteristics. Its effect reveals more evidently with cross flow. Within the present test conditions, the mass flow rates and outflow positions of FCHs have no distinct effect on the main flow structures.
基金Supported by Orthopaedic Research and Education FoundationZachary B Friedenberg,MD,Clinician Scientist Award to Dr.CuiQ
文摘Femoroacetabular impingement(FAI)is an increasingly recognized condition,which is believed to contribute to degenerative changes of the hip.This correlation has led to a great deal of interested in diagnosis and treatment of FAI.FAI can be divided into two groups:cam and pincer type impingement.FAI can lead to chondral and labral pathologies,that if left untreated,can progress rapidly to osteoarthritis.The diagnosis of FAI involves a detailed history,physical exam,and radiographs of the pelvis.Surgical treatment is indicated in anatomic variants known to cause FAI.The primary goal of surgical treatment is to increase joint clearance and decrease destructive forces being transmitted through the joint.Treatment has been evolving rapidly over the past decade and includes three primary techniques:open surgical dislocation,mini-open,and arthroscopic surgery.Open surgical dislocation is a technique for dislocating the femoral head from the acetabulum with a low risk of avascular necrosis in orderto reshape the neck or acetabular rim to improve joint clearance.Mini-open treatment is performed using the distal portion of an anterior approach to the hip to visualize and to correct acetabular and femoral head and neck junction deformities.This does not involve frank dislocation.Recently,arthroscopic treatment has gained popularity.This however does have a steep learning curve and is best done by an experienced surgeon.Short-to mid-term results have shown relatively equal success with all techniques in patients with no or only mild evidence of degenerative changes.Additionally,all techniques have demonstrated low rates of complications.
基金co-supported by the National Numerical Wind Tunnel Project(No.NNW2018-ZT2B04)the “973”Program of China(No.2015CB755800)。
文摘The multiple jets impingement heat transfer is widely applied in the wing anti-icing system.It is challenging to apply the similarity criterion to carry out the anti-icing experiments due to the complex flow and heat transfer behavior.In the present study,the full-scale slat model is used to carry out anti-icing experimental researches in a 2 m×3 m icing wind tunnel of China Aerodynamics Research and Development Center.The effects of icing parameters Liquid Water Content(LWC)and Median Volume Diameter(MVD)and hot air parameters(mass flow rate and temperature)on the thermal performance of an inner-liner anti-icing system with jets impingement heat transfer are studied.The effects of the experimental parameters are analyzed in detail by combining impingement and evaporation heat transfer mechanisms.The impingement hot air mass flow rate dramatically affects the heat transfer performance of the impingement stagnation region within the range of the experimental parameters.The temperature of impingement hot air and that of wing skin are approximately linear correlated.The experimental results show the effects of LWC and MVD on water film formation and runback ice accretion.The formation of water film is analyzed by an analytical method based on the wing skin temperature difference of dry and wet air conditions.
文摘The aim of this study is to examine the effects of local curvature and elastic wall effects of an isothermal hot wall for the purpose of jet impingement cooling performance.Finite element method was used with ALE.Different important parametric effects such as Re number(between 100 and 700),Ha number(between 0 and 20),elasticity(between 104 and 109),curvature of the surface(elliptic,radius ratio between 1 and 0.25) and nanoparticle volume fraction(between 0 and 0.05) on the cooling performance were investigated numerically.The results showed that the average Nu number enhances for higher Hartmann number,higher values of elastic modulus of partly flexible wall and higher nanoparticle volume fraction.When the magnetic field is imposed at the highest strength,there is an increase of3.85% in the average Nu for the curved elastic wall whereas it is 89.22% for the hot part above it,which is due to the vortex suppression effects.Nanoparticle inclusion in the base fluid improves the heat transfer rate by about 27.6% in the absence of magnetic field whereas it is 20.5% under the effects of magnetic field at Ha=20.Curvature effects become important for higher Re numbers and at Re=700,there is 14.11% variation in the average Nu between the cases with the lowest and highest radius ratio.The elastic wall effects on the heat transfer are reduced with the increased curvature of the bottom wall.
基金supported by Hunan Provincial Natural Science Foundation of China(No.2019JJ50701)。
文摘Heat transfer characteristics in a narrow confined channel with discrete impingement cooling were investigated using thermal infrared camera. Detailed heat transfer distributions and comparisons on three surfaces with three impact diameters were experimentally studied in the range of Reynolds number of 3000 to 30000. The experimental results indicated that the strong impingement jet leaded to a high strength heat transfer zone in the ΔX=±2.5D;range of the impact center,which was 1.3–2.5 times of the average heat transfer value of the impingement wall. With the same coolant mass flow rate, small diameter case had lower heat transfer coefficient on both inner wall and outside wall, while the impingement wall was insensitive to the impact diameter. The surface averaged Nusselt number of inner wall was only 43%–57% of impingement wall, while the outside wall can reach up to 80%–90%. The larger the diameter, the higher heat transfer enhancement and the smaller the channel flow resistance was observed in term of Reynolds number. The surface averaged Nusselt numbers were developed as the function of Reynolds number and the impingement height-to-diameter for further engineering applications.
基金Item Sponsored by National Natural Science Foundation of China(51474024,51334001)National Key Technology Research and Development Program of the 12th Five-year Plan of China(12FYP 2015BAF03B01)
文摘As a novel supersonic jet technology,preheating shrouded supersonic jet was developed to deliver oxygen into molten bath efficiently and affordably.However,there has been limited research on the jet behavior and impingement characteristics of preheating shrouded supersonic jets.Computational fluid dynamics（CFD）models were established to investigate the effects of main and shrouding gas temperatures on the characteristics of flow field and impingement of shrouded supersonic jet.The preheating shrouded supersonic jet behavior was simulated and measured by numerical simulation and jet measurement experiment respectively.The influence of preheating shrouded supersonic jet on gas jet penetration and fluid flow in liquid bath was calculated by the CFD model which was validated against water model experiments.The results show that the uptrend of the potential core length of shrouded supersonic jet would be accelerated with increasing the main and shrouding gas temperatures.Also,preheating supersonic jets demonstrated significant advantages in penetrating and stirring the liquid bath.
文摘AIM: To investigate the association between sports hernias and femoroacetabular impingement(FAI) in athletes.METHODS: Pub Med, MEDLINE, CINAHL, Embase, Cochrane Controlled Trials Register, and Google Scholar databases were electronically searched for articles relating to sports hernia, athletic pubalgia, groin pain, long-standing adductor-related groin pain, Gilmore groin, adductor pain syndrome, and FAI. The initial search identified 196 studies, of which only articles reporting on the association of sports hernia and FAI or laparoscopic treatment of sports hernia were selected for systematic review. Finally, 24 studies were reviewed to evaluate the prevalence of FAI in cases of sports hernia and examine treatment outcomes and evidence for a common underlying pathogenic mechanism.RESULTS: FAI has been reported in as few as 12% to as high as 94% of patients with sports hernias, athletic pubalgia or adductor-related groin pain. Cam-type impingement is proposed to lead to increased symphyseal motion with overload on the surrounding extra-articular structures and muscle, which can result in the development of sports hernia and athletic pubalgia. Laparoscopic repair of sports hernias, via either the transabdominal preperitoneal or extraperitoneal approach, has a high success rate and earlier recovery of full sports activity compared to open surgery or conservative treatment. For patients with FAI and sports hernia, the surgical management of both pathologies is more effective than sports pubalgia treatment or hip arthroscopy alone(89% vs 33% of cases). As sports hernias and FAI are typically treated by general and orthopedic surgeons, respectively, a multidisciplinary approach for diagnosis and treatment is recommended for optimal treatment of patients with these injuries.CONCLUSION: The restriction in range of motion due to FAI likely contributes to sports hernias; therefore, surgical treatment of both pathologies represents an optimal therapy.
文摘One of the most common pathologic processes seen in overhead throwing athletes is posterior shoulderpain resulting from internal impingement. "Internal impingement" is a term used to describe a constellation of symptoms which result from the greater tuberosity of the humerus and the articular surface of the rotator cuff abutting the posterosuperior glenoid when the shoulder is in an abducted and externally rotated position. The pathophysiology in symptomatic internal impingement is multifactorial,involving physiologic shoulder remodeling,posterior capsular contracture,and scapular dyskinesis. Throwers with internal impingement may complain of shoulder stiffness or the need for a prolonged warm-up,decline in performance,or posterior shoulder pain. On physical examination,patients will demonstrate limited internal rotation and posterior shoulder pain with a posterior impingement test. Common imaging findings include the classic "Bennett lesion" on radiographs,as well as articular-sided partial rotator cuff tears and concomitant SLAP lesions. Mainstays of treatment include intense non-operative management focusing on rest and stretching protocols focusing on the posterior capsule. Operative management is variable depending on the exact pathology,but largely consists of rotator cuff debridement. Outcomes of operative treatment have been mixed,therefore intense non-operative treatment should remain the focus of treatment.
基金Supported by the National Natural Science Foundation of China(51276090)
文摘Experimental investigation is conducted to investigate the flow and heat transfer performances of jet impingement cooling inside a semi-confined smooth channel.Effects of jet Reynolds number(varied from 10 000to 45000),orifice-to-target spacing(zn=1d—4d)and jet-to-jet pitches(xn=3d—5d,yn=3d—5d)on the convective heat transfer coefficient and discharge coefficient are revealed.For a single-row jets normal impingement,the impingement heat transfer is enhanced with the increase of impingement Reynolds number or the decrease of spanwise jet-to-jet pitch.The highest local heat transfer is achieved when zn/dis 2.For the double-row jets normal impingement,the laterally-averaged Nusselt number distributions in the vicinity of the first row jets impinging stagnation do not fit well with the single-row case.The highest local heat transfer is obtained when zn/dis 1.A smaller jetto-jet pitch generally results in a lower discharge coefficient.The discharge coefficient in the double-row case is decreased relative to the single-row case at the same impingement Reynolds number.
文摘The 3-D numerical computation of the flow and temperature fields for jet array impingement with initial crossflow investigates the effects of the jet-to-surface spacing, the impinging hole arrangement and the jet-to-crossflow mass flux ratio on heat transfer characteristics. The study shows that: (1) under the different jet-to-surface spacing, the impingement cooling with inline arrangement is better than that with staggered arrangement for a given jet-to-crossflow mass flux ratio;( 2 ) the value of jet-to-surface spacing impacts a complicated effect on the flow and heat transfer for jet array impingement; (3) as the ratio of crossflow-to-jet mass flux ratio increases, the cooling effectiveness on monotonous decrease for both inline and staggered arrangements at the same jet-to-surface spacing.
