This paper is mainly concerned with the development of a class of new
upwind methods and a novel treatment of the boundary condition based o
n the concept of kinetic flux vector splitting (KFVS) for solving invi
scid gasdynamic problems. KFVS utilizes the well-known connection that
the Euler equations of motion are the moments of the Boltzmann equati
on whenever the velocity distribution function is a Maxwellian. After
presentation of the analysis of the KFVS method in 1-D in detail, it i
s described how KFVS can be performed in a different manner to constru
ct various upwind methods for higher dimensions depending on the situa
tions. Next, it is shown how the KFVS formulation together with the sp
ecular reflection model of the kinetic theory of gases at the solid bo
undary lead to the development of a new treatment of the flow tangency
boundary condition which is robust, upwind and conservative and does
not require any further assumptions or the use of fictitious grid poin
ts. Finally, the present method is tested on a wide variety of problem
s to demonstrate its capability in obtaining accurate and wiggle-free
solutions.