how to calculate time averaged skin friction coefficient

adilio · May 25, 2016, 18:00

how to calculate time averaged skin friction coefficient and time averaged pressure coefficient in fluent. I simulated cases of NACA 0012 at angle of attacks 0,1,2,,,30 . I have plotted skin friction coefficient by Fluent Results but it seems there is kind of problem. None of the plot showed any negativity in friction coefficient. Please somebody help

`e` · May 25, 2016, 19:07

You'll need to store the time-averaged results by enabling "Data Sampling for Time Statistics" under Run Calculation. First, establish a developed flow (say the drag coefficient is oscillating or use a similar definition), and then enable the time statistics to capture the developed time-averaged solution.

sr71blackbird · January 28, 2017, 06:00

Hi all,

I am puzzled with the calculation of time-averaged pressure coefficient. I am now running a case of turbulent flow past a cylinder. Where should it be calculated in a flow field? The formula in Wikipedia suggests that there should be some freestream pressure value in the numerator, namely (P-P_infinity). In my domain inlet pressure boundary is of Neumann type and outlet is at P=0. So, will someone please guide me?

May 25, 2016, 19:07		#2
`e` Senior Member Join Date: Mar 2015 Posts: 892 Rep Power: 18	You'll need to store the time-averaged results by enabling "Data Sampling for Time Statistics" under Run Calculation. First, establish a developed flow (say the drag coefficient is oscillating or use a similar definition), and then enable the time statistics to capture the developed time-averaged solution. sr71blackbird likes this.

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January 28, 2017, 06:00		#3
sr71blackbird New Member Smruti Ranjan Jena Join Date: Jan 2017 Location: Odisha, India Posts: 5 Rep Power: 9	Hi all, I am puzzled with the calculation of time-averaged pressure coefficient. I am now running a case of turbulent flow past a cylinder. Where should it be calculated in a flow field? The formula in Wikipedia suggests that there should be some freestream pressure value in the numerator, namely (P-P_infinity). In my domain inlet pressure boundary is of Neumann type and outlet is at P=0. So, will someone please guide me?