VAWT Rotation UDF
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Hello everyone!
I have the following problem: I am modelling a transient problem about a VAWT (Vertical Axis Wind Turbine). I have a beam which turns around the vertical axis. Over this beam I have 3 wings which also turns around. But I don`t want they to turn at a fixed RPM. They must be in a fixed angle in each quadrant. I would like you to orient me about how to build my UDF. -How can I do for Fluent to recognize the "beam rotation angle" variable? -I have seen that I can use CG Motion to define velocities but I want to define positions. Is it possible? Or do I need to use velocities to do it? -Is it possible to work with profiles? By the moment the profile I used works badly. Thank you very much for your help :) (Explanatory image attached) |
You can define nodal positions as a function of time using the DEFINE_GRID_MOTION macro within the Moving/Deforming Mesh model.
I don't think profiles would work because they don't alter the flow field (only the boundaries). It'd be similar to changing the wind direction rather than moving the turbine blades. |
Quote:
I have created and load this UDF, but it doesn`t appear in Cell Zone ->Mesh Motion ->Zone Motion function. However it appears in dynamic mesh. Why? What is the diference between grid and cg motion? This is my udf file : #include "udf.h" DEFINE_CG_MOTION(lama1,dt,vel,omega,time,dtime) { /* reset velocities */ NV_S(vel, =, 0.0); NV_S(omega, =, 0.0); if (!Data_Valid_P()) return; if (time < 2.3) vel[1] = 0.04; else if (time < 3.1) vel[1] = 0; else if (time < 3.3) vel[1] = -7.2; else if (time < 3.6) vel[1] = -4.8; else if (time < 5.6) vel[1] = 0.7; else if (time < 5.7) vel[1] = -0.7; else if (time < 6.0) vel[1] = -1.0; else if (time < 6.9) vel[1] = 0.7; else if (time < 7.9) vel[1] = 0.8; else if (time < 8.0) vel[1] = 2.10; else if (time < 8.2) vel[1] = 1.70; else if (time < 9.2) vel[1] = 0; else vel[1] = 0; } |
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