mass average dissipation rate

Hi all,

I referred to the following links:-

https://help.altair.com/hwcfdsolvers/acusolve/topics/acusolve/post_processing_programs_acutrans.htm?zoom_highlight=acuTrans

https://help.altair.com/hwcfdsolvers/acusolve/topics/acusolve/udfgetosidata_acusolve_udf.htm

But I could not find a way to write the mass average dissipation rate using the UDF. I could only use the acusolve data translator to write it but I want to use UDF for the same. Do you know how to do it?

Thanks.

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v2022.1

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acupro

It looks like that variable might be available - just not documented.

Please try with the variable UDF_OSI_MAV_DISSIPATION - then please update whether that works.

Prabin Pradhananga_22497

It looks like that variable might be available - just not documented.

Please try with the variable UDF_OSI_MAV_DISSIPATION - then please update whether that works.

It seems it works but the values I got from the convert tool is different than the one I obtained using the UDF. I checked for the values in different time steps. It does not match exactly. May be because of averaging?

UDF => 0.542200827554

convert tool => 5.8018636166675785e-01

Prabin Pradhananga_22497

It seems it works but the values I got from the convert tool is different than the one I obtained using the UDF. I checked for the values in different time steps. It does not match exactly. May be because of averaging?

UDF => 0.542200827554

convert tool => 5.8018636166675785e-01

I just noticed the value for UDF matches with the dissipation rate in convert tool not with mass average dissipation rate.

acupro

It seems it works but the values I got from the convert tool is different than the one I obtained using the UDF. I checked for the values in different time steps. It does not match exactly. May be because of averaging?

UDF => 0.542200827554

convert tool => 5.8018636166675785e-01

It could be a difference in the timing of the data. The UDF is probably using the data from the end of the previous time step. In other words, does the UDF-reported value match more closely with the ConvertTool/AcuTrans data from the previous time step?

Does UDF_OSI_CURR_MAV_DISSIPATION appear closer to the ConvertTool values?

You might have access to

UDF_OSI_DISSIPATION
UDF_OSI_MAV_DISSIPATION
UDF_OSI_FMAV_DISSIPATION
UDF_OSI_CURR_DISSIPATION
UDF_OSI_CURR_MAV_DISSIPATION
UDF_OSI_CURR_FMAV_DISSIPATION

Does the UDF report different values for each of those?

Prabin Pradhananga_22497

It could be a difference in the timing of the data. The UDF is probably using the data from the end of the previous time step. In other words, does the UDF-reported value match more closely with the ConvertTool/AcuTrans data from the previous time step?

Does UDF_OSI_CURR_MAV_DISSIPATION appear closer to the ConvertTool values?

You might have access to

UDF_OSI_DISSIPATION
UDF_OSI_MAV_DISSIPATION
UDF_OSI_FMAV_DISSIPATION
UDF_OSI_CURR_DISSIPATION
UDF_OSI_CURR_MAV_DISSIPATION
UDF_OSI_CURR_FMAV_DISSIPATION

Does the UDF report different values for each of those?

I checked the values for different time step. UDF_OSI_MAV_DISSIPATION matches with dissipation rate in convert tool not with mass averaged dissipation rate.

Prabin Pradhananga_22497

I checked the values for different time step. UDF_OSI_MAV_DISSIPATION matches with dissipation rate in convert tool not with mass averaged dissipation rate.

UDF_OSI_DISSIPATION and UDF_OSI_MAV_DISSIPATION both of them report same values in udf and those values match with dissipation rate in the convert tool.

For the rest of the data, I got compilation error. It says:-

error: ‘UDF_OSI_CURR_MAV_DISSIPATION’ undeclared (first use in this function); did you mean ‘UDF_OSS_CURR_MAX_DISSIPATION’?
Real* e = udfGetOsiData( udfHd, "outlet_2 - Output", UDF_OSI_CURR_MAV_DISSIPATION ) ;

acupro

UDF_OSI_DISSIPATION and UDF_OSI_MAV_DISSIPATION both of them report same values in udf and those values match with dissipation rate in the convert tool.

For the rest of the data, I got compilation error. It says:-

error: ‘UDF_OSI_CURR_MAV_DISSIPATION’ undeclared (first use in this function); did you mean ‘UDF_OSS_CURR_MAX_DISSIPATION’?
Real* e = udfGetOsiData( udfHd, "outlet_2 - Output", UDF_OSI_CURR_MAV_DISSIPATION ) ;

Thank you. I will report your findings.

acupro

UDF_OSI_DISSIPATION and UDF_OSI_MAV_DISSIPATION both of them report same values in udf and those values match with dissipation rate in the convert tool.

For the rest of the data, I got compilation error. It says:-

error: ‘UDF_OSI_CURR_MAV_DISSIPATION’ undeclared (first use in this function); did you mean ‘UDF_OSS_CURR_MAX_DISSIPATION’?
Real* e = udfGetOsiData( udfHd, "outlet_2 - Output", UDF_OSI_CURR_MAV_DISSIPATION ) ;

I think that previous list is wrong. They should be 'MFAV' instead of 'FMAV' - but if none of the 'CURR' values work, this probably won't change that. Does

UDF_OSI_MFAV_DISSIPATION

work - and give the same as the other two, matching dissipation rate from Convert?

Prabin Pradhananga_22497

I think that previous list is wrong. They should be 'MFAV' instead of 'FMAV' - but if none of the 'CURR' values work, this probably won't change that. Does

UDF_OSI_MFAV_DISSIPATION

work - and give the same as the other two, matching dissipation rate from Convert?

Now it successfully compiles and UDF_OSI_MFAV_DISSIPATION in udf matches with mass flux averaged dissipation rate in convert tools. But the values are different.

UDF_OSI_DISSIPATION--->0.542200827554

UDF_OSI_MAV_DISSIPATION--->0.542200827554

UDF_OSI_MFAV_DISSIPATION--->0.576175336021

convert tool:

dissipation rate--->5.4220082755369303e-01

mass averaged dissipation rate--->5.7617533602060644e-01

mass flux average dissipation reate--->5.7617533602060644e-01

acupro

Now it successfully compiles and UDF_OSI_MFAV_DISSIPATION in udf matches with mass flux averaged dissipation rate in convert tools. But the values are different.

UDF_OSI_DISSIPATION--->0.542200827554

UDF_OSI_MAV_DISSIPATION--->0.542200827554

UDF_OSI_MFAV_DISSIPATION--->0.576175336021

convert tool:

dissipation rate--->5.4220082755369303e-01

mass averaged dissipation rate--->5.7617533602060644e-01

mass flux average dissipation reate--->5.7617533602060644e-01

If I can summarize:

1 - None of the CURR values work.

2 - UDF_OSI_DISSIPATION and UDF_OSI_MAV_DISSIPATION work - but both match the Convert Tool value for dissipation_rate

3 - UDF_OSI_MFAV_DISSIPATION works - and matches the Convert Tool value for mass_flux_averaged_dissipation_rate (as one would expect)

Is that all correct?

Prabin Pradhananga_22497

If I can summarize:

1 - None of the CURR values work.

2 - UDF_OSI_DISSIPATION and UDF_OSI_MAV_DISSIPATION work - but both match the Convert Tool value for dissipation_rate

3 - UDF_OSI_MFAV_DISSIPATION works - and matches the Convert Tool value for mass_flux_averaged_dissipation_rate (as one would expect)

Is that all correct?

Yes, that's correct.