| SPH(Smoothed particle hydrodynamics)is a meshless particle method.In the SPH method,fluid is regarded as a series of particles that carry physical information such as mass,density and energy.A weighted sum of smooth functions approximates the value of physical quantities of particles or the spatial derivative of physical quantities.SPH method has unparalleled advantages in computing large deformation and fluid interface fracture,and it is easy to deal with dynamic boundary and other problems.Based on the traditional SPH method,the numerical method is improved by mod-ifying the smooth function,Adams pressure gradient approximation,and introduction of cut-off cavitation model.Numerical studies were carried out on different problems respectively.The main work of this paper is as follows:(1)By improving the smooth function,the precision of the method is improved,and the numerical verification is carried out.(2)By improving the pressure gradient term in the momentum equation of particle approximation,and exerting the repelling force at the interfaces ensure the SPH method can capture the interface in multiphase flow simulation and eliminate the oscillation of physical quantities near the interface.The accuracy and robustness of the method in this paper are verified by examples of rayleigh-taylor interface instability,non-boussinesq lock exchange,dam break and bubble rising.Comparing different moment interface(particles)given point distribution,stress nephogram and stress time distribution,inter-face front distance physical quantities,in the numerical experiments shows that in this paper,the calculation results and experimental results accord with good values or other literature.(3)Considering the physical characteristics,adjusting the dynamic boundary con-ditions,using the Cut-off cavitation model,the SPH method is better to simulate the problem of high-speed water entry about the object.And it can be clearly observed objects around the cavitation phenomenon. |
