- **Main CFD Forum**
(*https://www.cfd-online.com/Forums/main/*)

- - **Rought estimation of dissipation energy
**
(*https://www.cfd-online.com/Forums/main/12676-rought-estimation-dissipation-energy.html*)

Rought estimation of dissipation energy
I am trying to estimate energy disspation and the corresponding heat enrgy from the large scale characteristics of turbulent flow. Especially, heat engergy from the fluid flow. I know exact calculation of it is almost impossible but, I need to estimate roughly.
Problem : Dissipation energy of flows in a moved large cube Dimension : L*B*H = 50m * 40* 30m Filling ratio : 95% of the height Large scale velocity u ~ 5m/s Dimensional scale L ~ 50m So, turbulent dissipation rate epsilon ~ u^3/L = 2.5 (Joule/(kg*sec)) Effective Mass in a cube ~ 4250 ton (because upper part of the fluid in a cube would be excited) Finally, total energy dissipation 1) m*epsilon ~ 4250 ton * 2.5 = 10625 kW If this energy could be changed to the heat energy 2) Q=4250 ton * 9,540Kj/KgK * dT ~ 10625MW temperature difference dT ~ 0.00026 But, I think the energy of 10625kW looks too much. So, please comment the above 1) and 2). Thank you for your valuable comments in advance. |

All times are GMT -4. The time now is 22:00. |