Great Video! I have a question regarding the angle of stall in the airfoil example at the end of the video: The critical angle of attack for airfoils with accompanying stall and reduction of lift force is usually about 12-15 degrees. Why does this occur in this example only at an angle of about 50 degrees ? Is it possible that you make a video showing a complete airfoil analysis in more detail? That would help me a lot!
Regarding my particular airfoil example, it was meant to run quickly and efficiently while still showing some-what of an estimated response of an air-foil behavior. What I called a "first-pass analysis" during the presentation to show the moving parts of how you could approach such a problem with automation. My setup was lacking in many significant ways in order to approach more realistic results and wasn't the intent of my presentation. You are correct in that my stall angle is way too high! If you are interested, I will add my thoughts in improving the results below: To improve the accuracy of the setup and response I would need to further address the mesh density of the computational domain especially around the partial cells of the model. I would also look to either increase the computational domain to include the full wing of the model leaving sufficient volume around the model to prevent any artificial results. Another approach uing the simpler or thin computational domain approach I used could be to use symmetry option when editing the computational domain to take into account the artificial boundaries of such a small computational domain that I used. Lastly, I would also add some global goals to ensure that the solver is converging its results across the full computational domain of the project. I would probably add an Av Density of the fluid, Av velocity, Av and max total pressure global goals. Also consider adding some of the turbulence global parameters if you think they are important in the calculation so that we can ensure full convergence of those parameters as well. I hope these suggestions help in your inquiry if you yourself are trying to setup such an airfoil design project with more meaningful results.
31:20 You keep as parameter for the wall "adiabatic wall" (therefore no heat exchange). Shouldn't you put a heat transfer coefficient so that your domain can exchange heat with the environment ?
Hello and thank you for your question! You are correct in changing the default outer wall thermal condition could possibly make the model setup more accurate. In this case we left it as adiabatic since it will help decrease calculation time and resources for my very first run of this project, eliminating heat transfer from the outer walls. Also, it is a best practice to keep your flow project setup as simple as possible at first and then begin to add more accuracy and detail to the model and setup. Another thought is that one could also locally apply all our thermal conditions manually to the model in the project design tree and any outer walls that are not specified will be assumed to be adiabatic. I hope this helps!
@@goengineer Yup, its nice, I tried 80MPa of compressed gas of nitrogen 2kg, as pressure+density and pressure+temperature, it yields the same, the shock wave and vibrations only missing, but at least the pressure waves are there, thanks for response.
great to learn!
Thank you!
Great Video!
I have a question regarding the angle of stall in the airfoil example at the end of the video: The critical angle of attack for airfoils with accompanying stall and reduction of lift force is usually about 12-15 degrees. Why does this occur in this example only at an angle of about 50 degrees ?
Is it possible that you make a video showing a complete airfoil analysis in more detail? That would help me a lot!
Regarding my particular airfoil example, it was meant to run quickly and efficiently while still showing some-what of an estimated response of an air-foil behavior. What I called a "first-pass analysis" during the presentation to show the moving parts of how you could approach such a problem with automation. My setup was lacking in many significant ways in order to approach more realistic results and wasn't the intent of my presentation. You are correct in that my stall angle is way too high! If you are interested, I will add my thoughts in improving the results below:
To improve the accuracy of the setup and response I would need to further address the mesh density of the computational domain especially around the partial cells of the model. I would also look to either increase the computational domain to include the full wing of the model leaving sufficient volume around the model to prevent any artificial results. Another approach uing the simpler or thin computational domain approach I used could be to use symmetry option when editing the computational domain to take into account the artificial boundaries of such a small computational domain that I used. Lastly, I would also add some global goals to ensure that the solver is converging its results across the full computational domain of the project. I would probably add an Av Density of the fluid, Av velocity, Av and max total pressure global goals. Also consider adding some of the turbulence global parameters if you think they are important in the calculation so that we can ensure full convergence of those parameters as well.
I hope these suggestions help in your inquiry if you yourself are trying to setup such an airfoil design project with more meaningful results.
31:20 You keep as parameter for the wall "adiabatic wall" (therefore no heat exchange). Shouldn't you put a heat transfer coefficient so that your domain can exchange heat with the environment ?
Hello and thank you for your question! You are correct in changing the default outer wall thermal condition could possibly make the model setup more accurate. In this case we left it as adiabatic since it will help decrease calculation time and resources for my very first run of this project, eliminating heat transfer from the outer walls. Also, it is a best practice to keep your flow project setup as simple as possible at first and then begin to add more accuracy and detail to the model and setup. Another thought is that one could also locally apply all our thermal conditions manually to the model in the project design tree and any outer walls that are not specified will be assumed to be adiabatic. I hope this helps!
can i get the assembly file?
does flow simulation able to handle blast or explosion simulations? thanks
Flow sim could simulate the pressure wave but not the blast event itself.
@@goengineer Yup, its nice, I tried 80MPa of compressed gas of nitrogen 2kg, as pressure+density and pressure+temperature, it yields the same, the shock wave and vibrations only missing, but at least the pressure waves are there, thanks for response.