# Discharge coefficient

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 March 29, 2023, 14:51 Discharge coefficient #1 New Member   Mikolaj Join Date: Oct 2022 Posts: 4 Rep Power: 3 Hi everyone, i'm trying to detemine discharge coefficient for simple problem - outflow of water from the large tank through small orifice. After few trials i am getting Cd=0.8. Cd=Qflow3D/Qtheoretical Any tips or suggestions ?

 March 29, 2023, 23:51 #2 Member   Sehroosh Join Date: Apr 2019 Location: Pakistan Posts: 52 Rep Power: 6 For finding out discharge coeffcient from model data, same orifice equation will work Qmodel = Cd x A x sqrt(2gh) Qflow3D/Qtheoretical works when Qtheoretical is determined without Cd. Last edited by MSM1985; March 30, 2023 at 01:43.

 March 30, 2023, 01:57 #3 New Member   Mikolaj Join Date: Oct 2022 Posts: 4 Rep Power: 3 Hi, thanks for reply. I dont think i described the problem in detail. I am trying to calculate Cd from equation Cd=Q_flow3D/(Asqrt(2gh)). (in my mind A x sqrt(2gh) = Qtheoretical ) To get Q_flow3D and A(area) i am placing baffle (flux surface) in orifice. To get h i am placing history probe. BC Ymin,Ymax,Zmin -wall; Xmin-fluid elevation, Xmax-outflow, Zmax- fluid fraction 0 After that train of thought i am getting Cd around 0.8, i was hoping for 0,6-0,65.

 March 30, 2023, 02:09 #4 Member   Sehroosh Join Date: Apr 2019 Location: Pakistan Posts: 52 Rep Power: 6 Cd varies from 0.61 - 0.98, depending upon orifice entrance conditions

 November 30, 2023, 05:23 #5 New Member   Rempel Jody Join Date: Mar 2022 Posts: 2 Rep Power: 0 How to accurately determine Cd value. basketball stars

 November 30, 2023, 23:35 #6 Member   Sehroosh Join Date: Apr 2019 Location: Pakistan Posts: 52 Rep Power: 6 most accurate method is physical model observations

 January 24, 2024, 01:09 #7 New Member   Mark Newton Join Date: Jan 2024 Posts: 4 Rep Power: 2 I have always wondered why it is not possible to make the maximum possible outflow of water? These are just my thoughts, nothing more.

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