Hello guys,
i have been working on this problem for quite some time now, i was able to plot Nu vs theta using poly lines,expressions and variables however the plot does not start from 0 degrees and doesn't end at 360 degrees. I have attached a picture of the resulting plot, as you can see it looks like an incomplete contour however as i see it the issue is that CFD-Post is considering the global coordinates as the origin of the circle.
I would appreciate any help on this.
Thank you,
Fadi el-Hajj
Dear Fadi el-Hajj
You can insert a polyline in the circumference of the oblique ( maybe a circle, rectangular....) and then export the function' Surface Nusselt Number' on the polyline to the Microsoft Excel. Then open the Excel program and insert graph along these data.
Please see my papers and you can imagine the nice results of this application.
You can export the required variable such as "Nu" or "Cp" on the desired surface (particle in this case) in ASCII format. This would fetch the X, Y coordinate data from mesh along with the intended variable.
Read this text file in MATLAB using fscanf function and then plot the data using the scatter function and show data with colormap and colorbar function.
Dear Fadi Hajj,
the picture you provided is unclear in terms of axes variables. Anyway, this plotting issue is quite simple in fluent (ver. 6.3 and similar) because, after simulation, from the menu' Plot-->XY Plot... you can choose your variable, the surface and the X Axis function (i.e. curve lenght or vector direction). You may plot data in fluent or write a file (click the Write to file checkbox in the Option panel).
In your case, I don't know the fluid dynamic details of your problem, but take care to choose the correct surface to plot, i.e. to consider the right interface, in order to have consistent plot. I hope this comment can help you.
Regards
Dear Fadi el-Hajj
You can insert a polyline in the circumference of the oblique ( maybe a circle, rectangular....) and then export the function' Surface Nusselt Number' on the polyline to the Microsoft Excel. Then open the Excel program and insert graph along these data.
Please see my papers and you can imagine the nice results of this application.
DEAR GHASSAN
I AM ALSO TRYING TO PLOT CP ON CIRCUMFERENCE OF CYLINDER. I HAVE DEFINED A POLYLINE FOR CIRCUMFERENCE NOW HOW CAN I TAKE THETA FROM 0 at the stagnation point TO 360 DEgrees at this polyline in CFD POST. THERE ARE X AND Y VARIABLES I s there any way I an convert these to theta.
Hello All
I assume spanwise length of cylinder in Z direction.
1. Create Iso - surface in fluent with Surface of Contant > Mesh > Z cordinate.
2. Give corresponding Z cordinate value as iso value. This value depends on where you want the surface. Be it the middle of cylinder , end of cylinder or anywhere in between.
3. Go to Plot X - Y > Select variable > Select the new iso surface made
4. Y axis - Variable we need ; X axis - Direction vector.
5. Convert X axis values using 'ACOS' function to degrees.
6. Thus Angle v/s Selected variable plot is obtained.
Adding more to the above answer for the calculation of Cp:
1. 'Mean Pressure coefficient' we get from Fluent is based on the 'Reference Values' given in the case and data. This data needs to be re arranged. For eg: 'Reference values' used for Drag, lift calculations will not be correct for Cp.
2. Direction vector - X axis gives position data in X cordinate which is equal to RCos (theta), R being the radius of cylinder.
3. Divide X data with R.
4. Obtained data in radians is to be converted to degree.
5. Use 'ACOS' in Excel to get the angle. In short DEGREE(ACOS(X)) will help in Excel.
6. Now, plot X vs Y - ----- > Angle (degree) vs Cp
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