[sunliming]

Hi,
I want to simulate flow over a moving wavy boundary, and the lower boundary is a sinusoidal solid wall, which propagates in stream-wise direction (x) with a constant phase speed c, thus every point of the boundary just oscillates up and down from its own zero position (oscillating vertically). Position of the lower boundary shape can be expressed as a function of x coordinate and time t:
y_wall=a*sin(k*(x-c*t))*F(t);
F(t)=1-exp(-t^2);
F(t) is used as a transitional function making it oscillating from y=0, and after sevral seconds F(t) rapidly converges to 1, yielding y_wall=a*sin(k*(x-c*t)).
Here is the reference document: Turbulent flow over a flexible wall undergoing a streamwise travelling wave motion.
Now the problem is how should I write the dynamicMeshDict to achieve such boundary movement?
Attached is the sketch.
Any hints will be appreciated!
Best regards!
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sunliming
sunliming59045@126.com
Tongji University, Shanghai

[TengWU]

Originally Posted by hjasak

Easy: have a look at your flux file and you will see you've got a flux through the wall.

This is because you have specified the velocity to be zero in the absolute reference frame and the wall is moving: the real velocity is not zero.

Use the movingWallVelocity boundary condition on U and all will be well. This corrects the normal component of your velocity b.c. to allow you to specify the b.c. with respect to the moving reference frame of your wall.

Clever or what? :-)

Hrv

Dear Prof. Hrvoje,

Recently, I'm simulating some harmonic forcing simulation (a rigid body is oscillating in the fluids). According your explanation if I use the fixedValue boundary condition for the wall the rigid body should not move at all. But it moves. Why?
On the other hand, if I use the movingWallVelocity boundary condition for the wall, the results I get is kind of bad comparing to the results obtained by using fixedValue boundary condition.
Suppose fixedValue boundary condition using relative velocity now, why should I use the movingWallVelocity boundary condition, as I guess it is the flux correction that makes the results looking bad. Am I right?

Thanks,
Teng

[arashfluid]

Hi friends,
I’m using icoFsiElasticNonLinULSolidFoam solver in OF-1.6-ext to solve pitching and plunging motion of 2D flexible airfoil problem.Furthermore, I have performed a few tests using pimpleFsiFoam developed by Charbel Habchi. However, I’ve not seen any differences between them. In order to impose pitching and plunging motion on the wing, I have used dynamicBodyFvMesh solver in dynamicMeshDict dictionary in the fluid region. In those aforementioned solvers, there are no options to set motion on wingsolid, hence I have applied the motion on the fluid side. In this situation, solid and fluid patches do not follow each other.In other words,wingsolid and wingfluid,each of them moves separately and do not affect each other.
How can I apply solidwing motion in OpenFOAM?
Do anybody know how can I implement RBFmotion in FSI?