I did an analysis in fluent for a flow over vanes with a constant inlet boundary condition (Mass flowrate). With this, I got positive lift, drag and moment. Thereafter, I perform the analysis again using profile as the inlet boundary condition to depict exactly what is happening in the system but this time I got positive lift and drag and a negative moment at zero degree deflection angle but from one degree deflection angle and above, I got negative lift and the rest positive. Trying to understand what is happening, I performed the analysis again using negative angle (example; -1 = 359, -2 = 358..... degrees) and I got positive lift and a negative moment.
Please, can someone tell me what could be the problem and how to fix it.
I am expecting increase in lift with increase in deflection angles.
Hi Uchenna,
it seems for me that you have a poor mesh and a postprocessing problem. In Fluent you often have such problems in postprocessing. Normally, I check such errors exactly in the same manner you did. I do very small changes and look at the results, if they change completely, it means, it is coming from the postprocessing tool. Try to plot the results by using only the nodes values and export the data in a txt file. This will help you to look at the calculated results without any manipulation, like interpolation etc. performed during postprocessing.
Best regards,
Antoni
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