# How can I get the Total Kinetic Energy of Fluid?

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 June 13, 2014, 16:19 How can I get the Total Kinetic Energy of Fluid? #1 New Member   Subodh Join Date: Sep 2013 Location: Canada Posts: 18 Rep Power: 5 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. Thanks

 July 5, 2014, 22:39 #2 Senior Member   Jeff Burnham Join Date: Apr 2010 Posts: 204 Rep Power: 9 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).

 July 6, 2014, 12:43 #3 New Member   Subodh Join Date: Sep 2013 Location: Canada Posts: 18 Rep Power: 5 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 ? Thanks

 July 6, 2014, 14:29 #4 Senior Member   Jeff Burnham Join Date: Apr 2010 Posts: 204 Rep Power: 9 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.

 July 6, 2014, 14:39 #5 New Member   Subodh Join Date: Sep 2013 Location: Canada Posts: 18 Rep Power: 5 Thanks , I am using Flow3d 10.0.3.1 Version..

 July 6, 2014, 15:01 #6 New Member   Subodh Join Date: Sep 2013 Location: Canada Posts: 18 Rep Power: 5 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 ?

 January 26, 2017, 03:30 #7 New Member   jadhav sarika Join Date: Jan 2017 Posts: 1 Rep Power: 0 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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