emilhedevang

Hi again, I have now had another look at the turbulence simulated from the "IEC Turbulence Simulator". It appears that the lengths scale L is ignored as well. Shown below is the content of the txt-files generates as a part of the turbulence simulation. The only thing I have changed is the value of the turbulence length scale, in the first case it is 50m and in the second it is 100m. Still, the outputs form the turbulence simulator are identical, byte for byte. Best regards, Emil ******************************************************************************** IECTurbulenceSimulator : 08-09-2010 12:11:12 Type of simulation Basic Mean horizontal wind speed 8m/s AlphaEpsilon 0.01 l 50m Gamma 1 Simulated turbulence field: Velocity components (u,v,w) (1,0,0) Number of points in each direction 16384, 8, 8 Fieldsize in meters 5200, 110, 110 dL1, dL2, dL3 0.3173828125m, 13.75m, 13.75m Spectrum type Kaimal Random seed 6 Output type HAWC High frequency compensation applied ******************************************************************************** IECTurbulenceSimulator : 08-09-2010 12:07:38 Type of simulation Basic Mean horizontal wind speed 8m/s AlphaEpsilon 0.01 l 100m Gamma 1 Simulated turbulence field: Velocity components (u,v,w) (1,0,0) Number of points in each direction 16384, 8, 8 Fieldsize in meters 5200, 110, 110 dL1, dL2, dL3 0.3173828125m, 13.75m, 13.75m Spectrum type Kaimal Random seed 6 Output type HAWC High frequency compensation applied ********************************************************************************

Hi Morten, Thanks you for the quick response. My though was indeed to just scale the velocity fluctuations to achieve the target variance as Alpha just scaled the spectrum and hence the variance. I'm guessing the program just calls the DLL with some fixed value of the Alpha parameter and hence ignores the user input. Best regards, Emil

Good evening, I have just downloaded an tried the IEC Turbulence Simulator from "http://www.wasp.dk/Products/weng/IECturbulenceSimulator.htm". The simulated turbulence does not seem depend on the Alpha parameter, indeed with the setting shown below I get identical results, byte for byte. In the first case the Alpha parameter is 0.01 while in the second it is 0.10. I would expect the Alpha parameter to influence the spectrum and thus the simulated turbulence. Am I mistaken? Best regards, Emil Hedevang ******************************************************************************** IECTurbulenceSimulator : 07-09-2010 18:14:54 Type of simulation Basic Mean horizontal wind speed 8m/s AlphaEpsilon 0.01 l 280m Gamma 0 Simulated turbulence field: Velocity components (u,v,w) (1,0,0) Number of points in each direction 16384, 8, 8 Fieldsize in meters 5200, 110, 110 dL1, dL2, dL3 0.3173828125m, 13.75m, 13.75m Spectrum type Kaimal Random seed 6 Output type HAWC High frequency compensation applied ******************************************************************************** IECTurbulenceSimulator : 07-09-2010 18:53:02 Type of simulation Basic Mean horizontal wind speed 8m/s AlphaEpsilon 0.1 l 280m Gamma 0 Simulated turbulence field: Velocity components (u,v,w) (1,0,0) Number of points in each direction 16384, 8, 8 Fieldsize in meters 5200, 110, 110 dL1, dL2, dL3 0.3173828125m, 13.75m, 13.75m Spectrum type Kaimal Random seed 6 Output type HAWC High frequency compensation applied ********************************************************************************