A Filtering Method For Gravitationally Stratified Flows

Gatti-Bono, Caroline ; Colella, Phillip

Lawrence Berkeley National Laboratory

关键词: Froude Number;    Gravity Waves;    Acoustics;    Simulation;    99;   

DOI  :  10.2172/922835
RP-ID  :  LBNL--57161
RP-ID  :  DE-AC02-05CH11231
RP-ID  :  922835

美国|英语

来源: UNT Digital Library

【 摘 要 】

Gravity waves arise in gravitationally stratified compressible flows at low Mach and Froude numbers. These waves can have a negligible influence on the overall dynamics of the fluid but, for numerical methods where the acoustic waves are treated implicitly, they impose a significant restriction on the time step. A way to alleviate this restriction is to filter out the modes corresponding to the fastest gravity waves so that a larger time step can be used. This paper presents a filtering strategy of the fully compressible equations based on normal mode analysis that is used throughout the simulation to compute the fast dynamics and that is able to damp only fast gravity modes.