waveTransmissive边界条件

[Aeronastro]

这个无反射边界条件具体怎么用呢？看了OpenFOAMwiki也是一头雾水。有两个疑问：
这个Ilnf和fieldIlnf的值怎么选呢？
这个条件如果用到出口有反压的情况，是否可以？

[CFD中文网]

@Aeronastro
看过这个描述么？

Description
    This boundary condition provides an advective outflow condition, based on
    solving DDt(psi, U) = 0 at the boundary.

    The standard (Euler, backward, CrankNicolson) time schemes are
    supported.  Additionally an optional mechanism to relax the value at
    the boundary to a specified far-field value is provided which is
    switched on by specifying the relaxation length-scale \c lInf and the
    far-field value \c fieldInf.

    The flow/wave speed at the outlet is provided by the virtual function
    advectionSpeed() the default implementation of which requires the name of
    the flux field \c (phi) and optionally the density \c (rho) if the
    mass-flux rather than the volumetric-flux is given.

    The flow/wave speed at the outlet can be changed by deriving a specialised
    BC from this class and over-riding advectionSpeed()  e.g. in
    waveTransmissiveFvPatchField the advectionSpeed() calculates and returns
    the flow-speed plus the acoustic wave speed creating an acoustic wave
    transmissive boundary condition.

    \heading Patch usage

    \table
        Property     | Description             | Required    | Default value
        phi          | flux field name         | no          | phi
        rho          | density field name      | no          | rho
        fieldInf     | value of field beyond patch | no      |
        lInf         | distance beyond patch for \c fieldInf | no |
    \endtable

    Example of the boundary condition specification:
    \verbatim
    myPatch
    {
        type            advective;
        phi             phi;
    }
    \endverbatim

Note
    If \c lInf is specified, \c fieldInf will be required; \c rho is only
    required in the case of a mass-based flux.

SourceFiles
    advectiveFvPatchField.C

[Aeronastro]

@cfd-china 看过了，不过还是不太明白是否能解决我提出的问题:confused:

[CFD中文网]

Henry最近添加了部分描述：点击查看