CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > OpenFOAM

Resisting torque on a moving mesh

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Display Modes
Old   January 11, 2010, 19:42
Default Resisting torque on a moving mesh
Join Date: Mar 2009
Location: Mannheim - Vincennes - Valenciennes, Deutchland - France
Posts: 34
Rep Power: 10
floooo is on a distinguished road

I am student. For my end of study's project, I try with 2 others students to study a new generation of vertical wind turbine with a CFD simulation .

We try to draw the curve of the Power coefficient CP according to lambda (the Tip Speed Ratio).

In order to have a reference, I are working in the same time on a Savonius wind turbine.

If we had a prototype and a wind tunnel, we would have to connect the wind turbine to a dynamic couple-meter. We would obtain the wished curve by making vary the resisting torque while keeping a constant speed of wind.

We started with fluent, but in this software it is not possible to put a resistant torque on a moving mesh.

So we made the opposite : we imposed a rotation speed of pales then we measured the couple engendered by the fluid on the rotor.

We simulated this with a stationary simulation and a rotational moving mesh boundary condition on blades. And then a in-stationary simulation with a moving mesh.

Both simulation give exactly the same results, the residuals are very good, but Cp curve is not realistic for lambda > 0.

For Lambda = 0, the result is very close to the theoretical value.

After a lot of work we concluded that the model is not good :
putting a rotating wind turbine in an air flow and measuring the couple engendered on the tree of rotation is not the same that measuring the rotation speed of a wind turbine on which we impose a resisting torque.

I have work on OpenFOAM during an internship period.
I have try the mixerVessel2D tutorial.

Is it possible to impose a resisting torque on a moving mesh area in OpenFOAM ??

Last edited by floooo; January 12, 2010 at 05:16.
floooo is offline   Reply With Quote

Old   February 4, 2010, 02:53
New Member
Join Date: Feb 2010
Posts: 7
Rep Power: 10
skshivas is on a distinguished road
It is possible to feed a Resistive torque and force in fluent for moving mesh model.or otherwise u can use Rigid body solutions (6-dof) Methods in CFX.
skshivas is offline   Reply With Quote

Old   March 14, 2010, 05:59
Senior Member
Join Date: Nov 2009
Posts: 122
Rep Power: 10
enry is on a distinguished road
Hi floooo
I'm also studying a VAWT. Are you sure that resutls obtained using a fixed rotation to the blades is not reasonable? I'm using this approach, and results seems to be good.

I have a question for you: I studied the problem using FLUENT, and now I'm trying to use OpenFOAM. I use sliding interface tecnique, but OF torque is not the same of FLUENT one. After a lot of simulation I think that the problem is maybe in boundary conditions. How have you set them for your problem?
Thank in advance.
enry is offline   Reply With Quote

Old   March 29, 2010, 20:18
Join Date: Mar 2009
Location: Mannheim - Vincennes - Valenciennes, Deutchland - France
Posts: 34
Rep Power: 10
floooo is on a distinguished road
Hi enry

I think that skshivas gave the solution. But it was too late for my report.
Currently I haven't the time to work on it.

There is an 6 DOF solver in Fluent. And I think it is possible to solve the problem using and UDF script.

I think the Fluent UDF file looks like this:

#include "udf.h"
DEFINE_SDOF_PROPERTIES(store, prop, dt, time, dtime)
prop[SDOF_MASS] = 10;
prop[SDOF_IZZ] = 200.;
if (time <= 0.3)
{ prop[SDOF_LOAD_F_X]=0; prop[SDOF_LOAD_F_Y]=0; prop[SDOF_LOAD_M_Z] = 20.0;

floooo is offline   Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
SnappyHexMesh for internal Flow vishwa OpenFOAM Native Meshers: snappyHexMesh and Others 24 June 27, 2016 08:54
Moving mesh part 2 lr103476 OpenFOAM Running, Solving & CFD 49 December 14, 2010 07:20
external flow with snappyHexMesh chelvistero OpenFOAM 11 January 15, 2010 20:43
CavitatingFoam with a moving mesh mass conservation error idosil OpenFOAM Running, Solving & CFD 3 November 27, 2007 18:27
Moving (structured) mesh Jesper CFX 5 February 2, 2007 04:43

All times are GMT -4. The time now is 00:52.