Dear all,

I am interested about studying the rotational cylinder in free flow (for incompressible flow). Looking around the Nektar's manual I realized that there is an option which, I think, allows to compute it, the MovingBody along with the Mapping (10.6.3 - 10.6.5) from Nektar++'s manual v4.4.0. I am using the example: the CylFlow_Mov_mapping as a reference one. However, I can not completely understand how it works. (I took the example from the 4.3.5 version)

First of all, that example is for a rotational cylinder or is it for a cylinder moving up and down on a periodic motion?

Tanking into account the first option,

The mapping function computes the new coordinates for the specified boundary, However, I do not understand why the function is specified in that way:

The value of the parameter A is not the radius of the cylinder, so it is not deifying a rotation over its center. Also, the new x coordinate is the same as before, so the cylinder just moved upwards or downwards.

Secondly, what is the MappingVel functions used for? I think it is used for specify the velocity on the new coordinates. However, the way it is defined, I think, it does not define a new velocity coordinates.

What I am misleading?

A part from that, I would also compute the aerodynamic forces on the moving surface, so I inserted the following:

<FORCE TYPE="MovingBody">
      <PARAM NAME="OutputFile">DragLift.frc</PARAM>
      <PARAM NAME="OutputFrequency">10</PARAM>
      <PARAM NAME="Boundary"> B[0] </PARAM>
</FORCE>

and also:

<MAPPING TYPE="Translation">
<COORDS>MovingBody</COORDS>
<VEL>MappingVel</VEL>
</MAPPING>

However, the file DragLift.frc is not generated.

Hope I have well explained and clarified all my inquiries.

Thank you very much,

Guillermo Suarez.