Based on Hong's theory, previous random models, and a generalized expression suitable for FFT calculation, the interaction between irregular waves and vertical walls is numerically simulated. The results of simu...Based on Hong's theory, previous random models, and a generalized expression suitable for FFT calculation, the interaction between irregular waves and vertical walls is numerically simulated. The results of simulation demonstrate that the wave energy changes with the incidence angle and the distance from the wall. Particularly, the Mach effect and the combined wave spectrum characteristics are analyzed in detail, which are significant in both theory and practice.展开更多
According to Einstein, General Relativity contains the essence of Mach’s ideas. Mach’s principle can be summarized by stating that the inertia of a body is determined by the rest of the mass-energy content of the un...According to Einstein, General Relativity contains the essence of Mach’s ideas. Mach’s principle can be summarized by stating that the inertia of a body is determined by the rest of the mass-energy content of the universe. Inertia here arises from mass-energy there. The latter, was a statement made by John Wheeler in his 1995 book, Gravitation and Inertia, coauthored by Ciufolini. Einstein believed that to be fully Machian, gravity would need a radiative component, an action-at-a-distance character, so that gravitational influences on a body from far away could be felt immediately. In 1960’s, Hoyle and Narlikar (HN) developed such a theory which was a gravitational version of the Absorber theory derived by Wheeler-Feynman for classical electrodynamics and later expanded upon by Davies and Narlikar for quantum electrodynamics. The HN-field equation has the same type of mass fluctuation terms as in the Woodward Mach effect thruster theory. The force equation, used to predict the thrust in our device, can be derived from the mass fluctuation. We outline a new method for deriving the force equation. We present new experimental tests of the thruster to show that the thrust seen in our device is not due to either heating or Dean Drive effects. Successful replications have been performed by groups in Austria and Canada, but their work is still pending in the peer review literature.展开更多
The Mach Effect Thruster (MET) is a propellant—less space drive which uses Mach’s principle to produce thrust in an accelerating material which is undergoing mass—energy fluctuations, [1]-[3]. Mach’s principle is ...The Mach Effect Thruster (MET) is a propellant—less space drive which uses Mach’s principle to produce thrust in an accelerating material which is undergoing mass—energy fluctuations, [1]-[3]. Mach’s principle is a statement that the inertia of a body is the result of the gravitational interaction of the body with the rest of the mass-energy in the universe. The MET device uses electric power of 100 - 200 Watts to operate. The thrust produced by these devices, at the present time, are small on the order of a few micro-Newtons. We give a physical description of the MET device and apparatus for measuring thrusts. Next we explain the basic theory behind the device which involves gravitation and advanced waves to incorporate instantaneous action at a distance. The advanced wave concept is a means to conserve momentum of the system with the universe. There is no momentun violation in this theory. We briefly review absorber theory by summarizing Dirac, Wheeler-Feynman and Hoyle-Narlikar (HN). We show how Woodward’s mass fluctuation formula can be derived from first principles using the HN-theory which is a fully Machian version of Einstein’s relativity. HN-theory reduces to Einstein’s field equations in the limit of smooth fluid distribution of matter and a simple coordinate transformation.展开更多
The influence of high temperature effects on the protrusion of Mach stem in strong shock reflection over a wedge was numerically investigated. A two-dimensional inviscid solver applies finite volume method and unstruc...The influence of high temperature effects on the protrusion of Mach stem in strong shock reflection over a wedge was numerically investigated. A two-dimensional inviscid solver applies finite volume method and unstructured quadrilateral grids were employed to simulate the flow. Theoretical analysis was also conducted to understand the phenomenon. Both numerical and theoretical results indicate a wall-jet penetrating forward is responsible for the occurrence of Mach stem protrusion. The protrusion degree seems to depend on the thermal energy buffer capacity of the testing gas. Approaches to increase the energy buffer capacity, such as vibrational relaxation, molecular dissociation, and increase of frozen heat caoacitv, all tend to escalate the orotrusion effect.展开更多
Mach reflection in steady supersonic flow is an important phenomenon having received extensive studies,among which simplified theoretical models to predict the size of Mach stem and other flow structure are of particu...Mach reflection in steady supersonic flow is an important phenomenon having received extensive studies,among which simplified theoretical models to predict the size of Mach stem and other flow structure are of particular interest.Past efforts for such models were based on inviscid assumption while in real cases the flow is viscous.Here in this paper we consider the influence of wedge boundary layer on the Mach stem height.This is done by including a simplified boundary layer model into a recently published inviscid model.In this viscous model,the wedge angle and the trailing edge height,which control the Mach stem height,are replaced by their equivalent ones accounting for the displacement effect of the wedge boundary layer,with the boundary layer assumed to be laminar or fully turbulent.This viscous model is shown to compare well with numerical results by computational fluid dynamics and gives a Mach stem height as function of the Reynolds number and Mach number.It is shown that due to the viscous effect,the Mach stem height is increased,through increasing the effective wedge angle.展开更多
文摘Based on Hong's theory, previous random models, and a generalized expression suitable for FFT calculation, the interaction between irregular waves and vertical walls is numerically simulated. The results of simulation demonstrate that the wave energy changes with the incidence angle and the distance from the wall. Particularly, the Mach effect and the combined wave spectrum characteristics are analyzed in detail, which are significant in both theory and practice.
文摘According to Einstein, General Relativity contains the essence of Mach’s ideas. Mach’s principle can be summarized by stating that the inertia of a body is determined by the rest of the mass-energy content of the universe. Inertia here arises from mass-energy there. The latter, was a statement made by John Wheeler in his 1995 book, Gravitation and Inertia, coauthored by Ciufolini. Einstein believed that to be fully Machian, gravity would need a radiative component, an action-at-a-distance character, so that gravitational influences on a body from far away could be felt immediately. In 1960’s, Hoyle and Narlikar (HN) developed such a theory which was a gravitational version of the Absorber theory derived by Wheeler-Feynman for classical electrodynamics and later expanded upon by Davies and Narlikar for quantum electrodynamics. The HN-field equation has the same type of mass fluctuation terms as in the Woodward Mach effect thruster theory. The force equation, used to predict the thrust in our device, can be derived from the mass fluctuation. We outline a new method for deriving the force equation. We present new experimental tests of the thruster to show that the thrust seen in our device is not due to either heating or Dean Drive effects. Successful replications have been performed by groups in Austria and Canada, but their work is still pending in the peer review literature.
文摘The Mach Effect Thruster (MET) is a propellant—less space drive which uses Mach’s principle to produce thrust in an accelerating material which is undergoing mass—energy fluctuations, [1]-[3]. Mach’s principle is a statement that the inertia of a body is the result of the gravitational interaction of the body with the rest of the mass-energy in the universe. The MET device uses electric power of 100 - 200 Watts to operate. The thrust produced by these devices, at the present time, are small on the order of a few micro-Newtons. We give a physical description of the MET device and apparatus for measuring thrusts. Next we explain the basic theory behind the device which involves gravitation and advanced waves to incorporate instantaneous action at a distance. The advanced wave concept is a means to conserve momentum of the system with the universe. There is no momentun violation in this theory. We briefly review absorber theory by summarizing Dirac, Wheeler-Feynman and Hoyle-Narlikar (HN). We show how Woodward’s mass fluctuation formula can be derived from first principles using the HN-theory which is a fully Machian version of Einstein’s relativity. HN-theory reduces to Einstein’s field equations in the limit of smooth fluid distribution of matter and a simple coordinate transformation.
文摘The influence of high temperature effects on the protrusion of Mach stem in strong shock reflection over a wedge was numerically investigated. A two-dimensional inviscid solver applies finite volume method and unstructured quadrilateral grids were employed to simulate the flow. Theoretical analysis was also conducted to understand the phenomenon. Both numerical and theoretical results indicate a wall-jet penetrating forward is responsible for the occurrence of Mach stem protrusion. The protrusion degree seems to depend on the thermal energy buffer capacity of the testing gas. Approaches to increase the energy buffer capacity, such as vibrational relaxation, molecular dissociation, and increase of frozen heat caoacitv, all tend to escalate the orotrusion effect.
基金supported by the Natural National Science Foundation of China(No.11802157).
文摘Mach reflection in steady supersonic flow is an important phenomenon having received extensive studies,among which simplified theoretical models to predict the size of Mach stem and other flow structure are of particular interest.Past efforts for such models were based on inviscid assumption while in real cases the flow is viscous.Here in this paper we consider the influence of wedge boundary layer on the Mach stem height.This is done by including a simplified boundary layer model into a recently published inviscid model.In this viscous model,the wedge angle and the trailing edge height,which control the Mach stem height,are replaced by their equivalent ones accounting for the displacement effect of the wedge boundary layer,with the boundary layer assumed to be laminar or fully turbulent.This viscous model is shown to compare well with numerical results by computational fluid dynamics and gives a Mach stem height as function of the Reynolds number and Mach number.It is shown that due to the viscous effect,the Mach stem height is increased,through increasing the effective wedge angle.
