The angle compensation method is adopted to detect sloshing waves by laser diffraction, in the case that the wavelength of the sloshing waves is much greater than that of the incident light. The clear diffraction patt...The angle compensation method is adopted to detect sloshing waves by laser diffraction, in the case that the wavelength of the sloshing waves is much greater than that of the incident light. The clear diffraction pattern is observed to be of asymmetry, involving orders, position and interval of the diffraction spots that are discovered during the light grazing incidence. It is found that the larger the angle of incidence is, the more obvious the asymmetry is. The higher the negative diffraction orders are, the smaller the intervals between spots are. On the contrary~ in the positive region, the higher the diffraction orders are, the larger the spot intervals are. The positive interval is larger than that of the same negative diffraction order. If the incident angle reaches 1.558 rad in the experiment, all positive diffraction orders completely vanish. Based on the mechanism of phase modulation and with the Fourier transform method, the relations between the incident angle and position, interval spaces, and orders of diffraction spots are derived theoretically. The theoretical calculations are compared with the experimental data, and the comparison shows that the theoretical calculations are in good agreement with the experimental measurement.展开更多
Liquid sloshing in tanks is a very complex nonlinear free surface fluid flow problem,which must be considered in most of the marine engineering problems such as naval architecture,offshore engineering and so on.Violen...Liquid sloshing in tanks is a very complex nonlinear free surface fluid flow problem,which must be considered in most of the marine engineering problems such as naval architecture,offshore engineering and so on.Violent liquid sloshing in large containers can damage the tank structure due to the direct liquid impacting action.Sloshing also affects the capsizing process of the liquid cargo ship.Some works on mitigating sloshing by using all kinds of the baffles were thus followed with interests.Oil layers with thinner thickness were shown to reduce the sloshing load of water in tanks.The sloshing characteristics in tanks with different sizes were different,therefore,scaling effect of sloshing should also be considered.Sloshing in a tank can also be used as tuned liquid dampers(TLDs)to dampen wind,wave and flow-induced motions of floating or fixed marine platforms.This paper present an overview on recent advances of liquid sloshing hydrodynamics including sloshing mitigation by using anti-sloshing baffle,layered fluids sloshing,scaling effect of sloshing and TLDs.展开更多
For violent sloshing,the flow field becomes complicated and 3-D effect is non-negligible.In addition to the excitation direction,the wave can also propagate perpendicular to the excitation direction.Due to the superpo...For violent sloshing,the flow field becomes complicated and 3-D effect is non-negligible.In addition to the excitation direction,the wave can also propagate perpendicular to the excitation direction.Due to the superposition of waves from different directions,the impact pressure imposed on the wall of the tank may increase.In this paper,our in-house solver MPSGPU-SJTU based on moving particle semi-implicit(MPS)method coupled with GPU techniques is employed for the liquid sloshing simulation,to study the factors leading to the 3-D effect.Firstly,a series of sloshing simulations are carried out to validate the reliability of present solver.Then,the sensitivity of 3-D effect against some parameters,such as excitation frequency,dimensions of the tank and filling ratio,is checked through numerical simulations.Time histories of pressure obtained by 2-D and 3-D simulations are compared to judge the occurrence of 3-D effect.It concludes that effects of those parameters are all significant.展开更多
基金Supported by the Open Research Fund of State Key Laboratory of Transient Optics and Photonics of Chinese Academy of Sciences under Grant No SKLST201508the China Postdoctoral Science Foundation Funded Project under Grant No 2015M580945the Government of Chaoyang District Postdoctoral Research Foundation
文摘The angle compensation method is adopted to detect sloshing waves by laser diffraction, in the case that the wavelength of the sloshing waves is much greater than that of the incident light. The clear diffraction pattern is observed to be of asymmetry, involving orders, position and interval of the diffraction spots that are discovered during the light grazing incidence. It is found that the larger the angle of incidence is, the more obvious the asymmetry is. The higher the negative diffraction orders are, the smaller the intervals between spots are. On the contrary~ in the positive region, the higher the diffraction orders are, the larger the spot intervals are. The positive interval is larger than that of the same negative diffraction order. If the incident angle reaches 1.558 rad in the experiment, all positive diffraction orders completely vanish. Based on the mechanism of phase modulation and with the Fourier transform method, the relations between the incident angle and position, interval spaces, and orders of diffraction spots are derived theoretically. The theoretical calculations are compared with the experimental data, and the comparison shows that the theoretical calculations are in good agreement with the experimental measurement.
基金Projects supported by the National Natural Science Foundation of China(Grant No.52171256).
文摘Liquid sloshing in tanks is a very complex nonlinear free surface fluid flow problem,which must be considered in most of the marine engineering problems such as naval architecture,offshore engineering and so on.Violent liquid sloshing in large containers can damage the tank structure due to the direct liquid impacting action.Sloshing also affects the capsizing process of the liquid cargo ship.Some works on mitigating sloshing by using all kinds of the baffles were thus followed with interests.Oil layers with thinner thickness were shown to reduce the sloshing load of water in tanks.The sloshing characteristics in tanks with different sizes were different,therefore,scaling effect of sloshing should also be considered.Sloshing in a tank can also be used as tuned liquid dampers(TLDs)to dampen wind,wave and flow-induced motions of floating or fixed marine platforms.This paper present an overview on recent advances of liquid sloshing hydrodynamics including sloshing mitigation by using anti-sloshing baffle,layered fluids sloshing,scaling effect of sloshing and TLDs.
基金National Natural Science Foundation of China(Grant Nos.51909160,51879159)the National Key Research and Development Program of China(Grant Nos.2019YFB1704200,2019YFC0312400)+1 种基金the Chang Jiang Scholars Program(Grant No.T2014099)the Innovative Special Project of Numerical Tank of Ministry of Industry and Information Technology of China(Grant No.2016-23/09).
文摘For violent sloshing,the flow field becomes complicated and 3-D effect is non-negligible.In addition to the excitation direction,the wave can also propagate perpendicular to the excitation direction.Due to the superposition of waves from different directions,the impact pressure imposed on the wall of the tank may increase.In this paper,our in-house solver MPSGPU-SJTU based on moving particle semi-implicit(MPS)method coupled with GPU techniques is employed for the liquid sloshing simulation,to study the factors leading to the 3-D effect.Firstly,a series of sloshing simulations are carried out to validate the reliability of present solver.Then,the sensitivity of 3-D effect against some parameters,such as excitation frequency,dimensions of the tank and filling ratio,is checked through numerical simulations.Time histories of pressure obtained by 2-D and 3-D simulations are compared to judge the occurrence of 3-D effect.It concludes that effects of those parameters are all significant.
