Alternative boundary treatment on cell-centered scheme
I used ghost cell concept for euler solver but confused how can I compute gradient of flow properties at boundary face for viscous flux.
Because I need gradients of velocity and Temperature at ghost cell for face centered properties, but I have no idea about this.
For your understanding I'd like to use modified gradient described in Blazek's
Is there any alternative or breakthrough?
In a FV method is quite natural to prescribe the flux at a boundary. FOr example
zero flux on a not-permeable wall, prescribed flow rate on inflow, etc
zero convective flux a not-permeable wall, prescribed flux for fixed flow rate. The diffusive flux is imposed such that the velocity on a boundary is prescribed, for example, at first order, a normal derivatives of the velocity on a wall is
mu*du/dy|wall -> mu * (u(wall+1) - u(wall-1))/(2*dy) = mu*u(wall+1)/dy
quite natural if you have adiabatic or fixed heat flux q = -k*Grad T
and so on ...
Thank you for your kind reply with example.
I guess I understood your explanation. But I'd like to be checked the thought below and get some more about boundary condition.
How can I implement viscous flux for subsonic boundary condition?
Thank you in advance :)
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