Acoustically Nonreflecting and Reflecting Boundary Conditions for Vortcity Injection in Compressible Solvers
Acoustically Nonreflecting and Reflecting Boundary Conditions for Vortcity Injection in Compressible Solvers
复制标题
可压缩求解器中涡度注入的声学无反射和反射边界条件
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
T. Poinsot
中科院分区：
文献类型：
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作者：
Nicolas Guezennec;T. Poinsot
在许多直接数值模拟或大涡模拟中，需要将湍流注入到计算域中。这项任务在可压缩配方中可能会变得困难，因为在可压缩配方中，声波也必须控制在边界上。本文比较了三种特征边界条件对孤立涡或湍流的影响，同时控制了边界的声学行为。前两种方法是用于引入声波的常用特征边界条件(反射和非反射N-S特征边界条件技术)。第三种是构造一种新的边界条件(涡流特征边界条件)，在声波不反射的情况下引入湍流或涡流。这三种方法在两个理论算例中进行了验证：1)注入孤立涡和2)注入各向同性湍流。这两个测试首先在静流中进行，然后在声波向入口处传播并与涡量喷射相互作用的区域中进行。结果表明，反射Navier-Stokes特征边界条件能够正确地引入涡量波(涡旋或湍流)和全反射声波。为了引入涡量波并让声波在无反射的情况下传播，需要涡流特征边界条件，而不能使用通常的N-S特征边界条件方法。
Injecting turbulence into computational domains is needed in many direct numerical simulations or large eddy simulations. This task may become difficult in compressible formulations in which acoustic waves must also be controlled on boundaries. In this paper, three characteristic boundary conditions are compared with inject isolated vortices or turbulence into the flow and control the acoustic behavior of the boundary at the same time. The first two methods are the usual characteristic boundary conditions (reflecting and nonreflecting Navier―Stokes characteristic boundary-condition techniques) used to introduce acoustic waves. The third one is a new boundary condition (vortical-flow characteristic boundary condition) constructed to introduce turbulence or vortices while being nonreflecting for acoustic waves. The three methods are tested in two academic cases: 1) injection of an isolated vortex and 2) injection of isotropic turbulence. These two tests are first performed in a quiet flow and then in a domain in which acoustic waves propagate toward the inlet and interact with vorticity injection. Results show that the reflecting Navier―Stokes characteristic boundary condition performs correctly to introduce vorticity waves (vortices or turbulence) and totally reflect acoustic waves. To introduce vorticity waves and let acoustic waves propagate without reflection, the vortical-flow characteristic boundary condition is required and the usual Navier―Stokes characteristic boundary-condition method cannot be used.