New ideas on governing equations of fluid dynamics

作     者：Chaoqun Liu Chaoqun Liu

作者机构：Department of MathematicsUniversity of Texas at ArlingtonArlingtonTexas76019USA 

出 版 物：《Journal of Hydrodynamics》 (水动力学研究与进展B辑（英文版）)

年 卷 期：2021年第33卷第4期

页      面：861-866页

核心收录：

学科分类：080704[工学-流体机械及工程] 080103[工学-流体力学] 08[工学] 0807[工学-动力工程及工程热物理] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 0701[理学-数学] 0801[工学-力学（可授工学、理学学位）] 0702[理学-物理学] 0812[工学-计算机科学与技术（可授工学、理学学位）] 

基　　金：This work was mainly supported by the Department of Mathematics of University of Texas at Arlington as the author is the full-time professor in UTA and all students and visitors were housed by UTA 

主　　题：New fluid kinematics strain stress Newton’s law Navier-Stokes new fluid dynamics 

摘      要：Classical fluid kinematics or Cauchy-Stokes decomposition mistreated vorticity as fluid rotation and mixed flow stretching with *** fluid dynamics or Navier-Stokes(N-S)equations are based on the classical kinematics and treated vorticity as null in contribution of forces and mixed the stretching force with the shearing force,which is not consistent with the Galilean invariancy.N-S equations also neglect the flow *** is believed that N-S equations may work for incompressible and laminar flow but are not satisfied for turbulent flow and compressible flow especially for high-speed *** on Liutex,new fluid kinematics has been established by Liu in 2021,which gives a Liutex-based principal coordinate system and a new principal decomposition in that system,which has been transferred back to the original Cartesian coordinate *** principal decomposition of velocity gradient tensor has four parts which are called rotation,stretching,anti-symmetric shearing and symmetric *** forces are derived according to the four parts of the velocity gradient *** to the new fluid kinematics,it is reported in this letter that based on the principal decomposition,a new relation between the velocity gradient tensor and stress-rate tensor has been established to form a new fluid dynamics equation to govern fluid *** new governing equation may be applicable to both laminar flow and turbulent flow,and both incompressible flow and compressible flow including high-speed flow for reasonable results with reasonable *** numerical experiment is needed to verify.