energy spectra from LES simulations

kumar · October 29, 2009, 10:42

Hello Everybody,

I am using lesInterfoam for running some two phase simulations using the one eq eddy model.
I am doing a mesh convergence study, so i want to compare the energy spectra from different meshes.

I have successfully made a utility called KE which extracts the Total kinetic energy from all the time steps, I made it by changing a few lines of the Lamda2 utility and compiling it, and the utility works fine. i have used something like "0.5*U&U" to extract the Total Kinetic energy. I got this from a post.

Actually I am new to this kind of energy spectra analysis, so iam not sure how to use the total kinetic energy and produce a energy spectra. Any comments from experienced LES users is welcome. Also any literature explaining how to extract energy spectra from Total Kinetic Energy is also welcome.

bye
wiith regards
K.Suresh kumar

lx882211 · February 22, 2016, 11:14

Quote:

Originally Posted by kumar

Hello Everybody,

I am using lesInterfoam for running some two phase simulations using the one eq eddy model.
I am doing a mesh convergence study, so i want to compare the energy spectra from different meshes.

I have successfully made a utility called KE which extracts the Total kinetic energy from all the time steps, I made it by changing a few lines of the Lamda2 utility and compiling it, and the utility works fine. i have used something like "0.5*U&U" to extract the Total Kinetic energy. I got this from a post.

Actually I am new to this kind of energy spectra analysis, so iam not sure how to use the total kinetic energy and produce a energy spectra. Any comments from experienced LES users is welcome. Also any literature explaining how to extract energy spectra from Total Kinetic Energy is also welcome.

bye
wiith regards
K.Suresh kumar

Hi, could you tell me how to get the TKE, which parameter should i monitor? Thanks.

Bazinga · February 23, 2016, 13:25

You can use probes to monitor the velocity fluctuations at one location at each time steps. With the time series you can calculate your fluctuations and thus your TKE.
You can also use the fieldAverage function object to record prime2mean with which you can also calculate a time averaged TKE in the whole domain.
Check the forum for an explanation of both options.
Hope that helps.

October 29, 2009, 10:42	energy spectra from LES simulations	#1
kumar Senior Member Suresh kumar Kannan Join Date: Mar 2009 Location: Luxembourg, Luxembourg, Luxembourg Posts: 129 Rep Power: 17	Hello Everybody, I am using lesInterfoam for running some two phase simulations using the one eq eddy model. I am doing a mesh convergence study, so i want to compare the energy spectra from different meshes. I have successfully made a utility called KE which extracts the Total kinetic energy from all the time steps, I made it by changing a few lines of the Lamda2 utility and compiling it, and the utility works fine. i have used something like "0.5*U&U" to extract the Total Kinetic energy. I got this from a post. Actually I am new to this kind of energy spectra analysis, so iam not sure how to use the total kinetic energy and produce a energy spectra. Any comments from experienced LES users is welcome. Also any literature explaining how to extract energy spectra from Total Kinetic Energy is also welcome. bye wiith regards K.Suresh kumar

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February 23, 2016, 13:25		#3
Bazinga Senior Member Join Date: Jun 2012 Location: Germany, Bochum Posts: 230 Rep Power: 16	You can use probes to monitor the velocity fluctuations at one location at each time steps. With the time series you can calculate your fluctuations and thus your TKE. You can also use the fieldAverage function object to record prime2mean with which you can also calculate a time averaged TKE in the whole domain. Check the forum for an explanation of both options. Hope that helps.