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How can I get the Total Kinetic Energy of Fluid?

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Old   June 13, 2014, 16:19
Default How can I get the Total Kinetic Energy of Fluid?
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Subodh
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Hi,
I would like to know how can i get the total Kinetic Energy of the fluid ,which is being disturbed by an object moving solely due to buoyancy.

I need Total K.E at each time interval to determine the added mass as the object moves through the fluid along z axis.

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Old   July 5, 2014, 22:39
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Jeff Burnham
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I think you need:

Analyze > Probe > General History Data > Mass-Averaged Mean Kinetic Energy, and select Text as output type at the bottom.

This is the kinetic energy corresponding to the mean (non-turbulent) velocity. Remember that velocity can be thought of as a time-average mean component + a fluctuating component; this variable is the time-average mean only. It's mass-averaged by summing the K.E. in each cell x the mass of fluid in that cell and dividing the sum by the mass in all cells.

MKE = sum(KEi * mi)/sum(mi) for cells i = 1 to n

Mass-Averaged Turbulent Kinetic Energy works the same way for the fluctuating velocity component (if you're using a RANS turbulence model like RNG).
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Old   July 6, 2014, 12:43
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Thanks a lot Jeff for reply,

I am using RNG model , but in my General history data I can see "Estimated mean kinetic energy" is it the same as Mass-Averaged Mean Kinetic Energy?

Also while going through the theory of RANS turbulence model I found that the instantaneous kinetic energy k(t) of a turbulent flow is the sum of "Mean kinetic energy " and "Turbulent kinetic energy "

So from Flow3d General history data ,can I use "Estimated Mean Kinetic energy +Average Turbulent Kinetic Energy" so as to get the instantaneous Kinetic Energy ?

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Old   July 6, 2014, 14:29
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That sounds right. I'm not familiar with the 'estimated mean kinetic energy' output. It might be that you're using an older version than I'm familiar with. If the definition is the same, then yes, you can combine MKE and TKE to get the total KE.
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Old   July 6, 2014, 14:39
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Thanks ,

I am using Flow3d 10.0.3.1 Version..
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Old   July 6, 2014, 15:01
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Also Is it possible to calculate the forces due to collision between two objects inside fluid while using GMO model.

In my case its a underwater spherical ice model hitting a floating platform.

In General History data output I can see pressure force and shear force output.

Does that includes the impact force due to collision of two bodies too or is it just pressure due to the fluid flow created by moving object ?
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Old   January 26, 2017, 03:30
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jadhav sarika
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What is the meaning of estimated mean kinetic energy in flow 3d and what location it is calculated in stepped spillway.
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