[CFD POST ] Averaging Values for one direction

max3.2 · April 27, 2011, 07:49

Hello,

I've got a little Problem with Post. I am simulating a Channel Flow where x is flow direction, y is depth and z is height. For calculating some loss coeffs (a quotient of different pressures), I used the areaAve expression at different Planes in x-normal-direction before and behind a blade profile, and so getting a constant value.
Now I'm trying the following: With still fixed x-value (the Plane Location), I want to average the variable value (TotalPressure) in the y-direction for every height (z) for plotting a loss coeffs vs. channel height chart.
I cant find a y-average function or something like that....can anybody help?
Thanks in advance.

Best Regards
Max

stumpy · April 27, 2011, 09:39

I guess you could create line objects rather than planes, then use the lengthAve function.
Note that when averaging Total Pressure you should use massFlowAve, not areaAve. areaAve can be used for Static Pressure.

max3.2 · April 27, 2011, 10:11

Quote:

Originally Posted by stumpy

Note that when averaging Total Pressure you should use massFlowAve, not areaAve. areaAve can be used for Static Pressure.

Thanks for the hint =)

Quote:

Originally Posted by stumpy

I guess you could create line objects rather than planes, then use the lengthAve function.

If i get what you mean: Yes, i can create lines with z,x=const and the use lenght average on each. then create a plot with the linevalues. the experimental data i have to compare to deals with approx. 100 values, also, there is a thesis with a plot with a lot more points (curves are really smooth).
isnt there a way to do this auto? i thought about integrating and dividing by the (constant) lenght. but i still cant find a way to do it so i get an exp oder var which is only a f(z)

max3.2 · April 28, 2011, 10:37

Nobody?

Isnt there any way to "collapse" plane values (yAve()@Plane, etc..) to eliminate the y-coord? Or any other way to extract such data,even to a dat file or smth..

max3.2 · May 4, 2011, 03:49

A little bit of news: I contacted CFX Support and maybe getting an answer soon. It seems that there is a Script doing it. I will post a solution if there's one.

ghorrocks · May 4, 2011, 07:23

Use the record session option in CFD-Post to record a few steps like making a plane and extracting values. Then edit the session file and insert some perl and you have it.

max3.2 · May 4, 2011, 14:15

Hi,

CFX supported me with a session file doing so.

Max

April 27, 2011, 07:49	[CFD POST ] Averaging Values for one direction	#1
max3.2 Member Max Join Date: Apr 2011 Posts: 47 Rep Power: 14	Hello, I've got a little Problem with Post. I am simulating a Channel Flow where x is flow direction, y is depth and z is height. For calculating some loss coeffs (a quotient of different pressures), I used the areaAve expression at different Planes in x-normal-direction before and behind a blade profile, and so getting a constant value. Now I'm trying the following: With still fixed x-value (the Plane Location), I want to average the variable value (TotalPressure) in the y-direction for every height (z) for plotting a loss coeffs vs. channel height chart. I cant find a y-average function or something like that....can anybody help? Thanks in advance. Best Regards Max

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April 27, 2011, 09:39		#2
stumpy Senior Member Join Date: Apr 2009 Posts: 531 Rep Power: 21	I guess you could create line objects rather than planes, then use the lengthAve function. Note that when averaging Total Pressure you should use massFlowAve, not areaAve. areaAve can be used for Static Pressure.

April 28, 2011, 10:37		#4
max3.2 Member Max Join Date: Apr 2011 Posts: 47 Rep Power: 14	Nobody? Isnt there any way to "collapse" plane values (yAve()@Plane, etc..) to eliminate the y-coord? Or any other way to extract such data,even to a dat file or smth..

May 4, 2011, 03:49		#5
max3.2 Member Max Join Date: Apr 2011 Posts: 47 Rep Power: 14	A little bit of news: I contacted CFX Support and maybe getting an answer soon. It seems that there is a Script doing it. I will post a solution if there's one.

May 4, 2011, 07:23		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	Use the record session option in CFD-Post to record a few steps like making a plane and extracting values. Then edit the session file and insert some perl and you have it.

May 4, 2011, 14:15		#7
max3.2 Member Max Join Date: Apr 2011 Posts: 47 Rep Power: 14	Hi, CFX supported me with a session file doing so. Max