CFD results, can somebody help

I have carried out CFD on aircraft wing based following these step https://help.sim-flow.com/tutorials/wing

I obtain these results





I havent done CFD before there is no documents to explain the results. Like is the force coefficient, What are the x, y and z axis showing. What are the 3 line on the cofficient graph. What are the velocity and streamline graphs showing. so on. Im trying to analysis them but dont understand what im looking at.

Cheers

Ok,
so first of you have 3 lines showing you the values of Cl Cm & Cd these are coefficients relating to lift, drag and pitching moment. Depending on how you setup the CFD depends on why the vary with the time domain but im going to assume that this is a steady state simulation and that the variation is essentially how long it took the simulation to converge.

The second graph appears to show air speed over the aerofoil, and the third graph (the most interesting) it shows the pressure of the air flow. Now as you can see as speed increases pressure decreases (and vice versa) leaving a higher pressure underneath the aerofoil then above the aerofoil, this pressure difference is what generates the upwards force known as lift.

Now you have here is a 2D cross section in steady state flow with zero wing pitch angle, in reality trying to model this is very complex and you need to be very careful to mesh correctly and ensure you are very careful with boundary layer effects and things but this appears to be a very simple model just showing what happens to air pressure and speed.

Thank you

sorry to be a bother, I had another question and just check.

So 1st graph shows, coefficent (lift, drag, pitch)
2nd graph shows, velocity
3rd show, pressure (i though that one just showed velocity with streamlines)

What info can i get from these graphs?

This is what i gathered.
1st graph i dont know what info i can extract from it. stuck on that one.
2nd graph you can see high velocity on top and low on bottom. Highest and lowest localised at the tips of the wing. Velocity decrease in intensity outwards from the wing. velocity decreases as it progreses to the rear of the wing. this will effect the pressure and lift.
3rd graph you can see high pressure below and low above, this is inrelation to the high an low velocity from graph 2. moderate pressure is located on top (green) and high pressure is located on bottom (red). Low pressure (green) on top and high pressure on bottom should be improve to improve lift coefficient through aerodynamic improvements.

Ok,
so first of you have 3 lines showing you the values of Cl Cm & Cd these are coefficients relating to lift, drag and pitching moment. Depending on how you setup the CFD depends on why the vary with the time domain but im going to assume that this is a steady state simulation and that the variation is essentially how long it took the simulation to converge.

The second graph appears to show air speed over the aerofoil, and the third graph (the most interesting) it shows the pressure of the air flow. Now as you can see as speed increases pressure decreases (and vice versa) leaving a higher pressure underneath the aerofoil then above the aerofoil, this pressure difference is what generates the upwards force known as lift.

Now you have here is a 2D cross section in steady state flow with zero wing pitch angle, in reality trying to model this is very complex and you need to be very careful to mesh correctly and ensure you are very careful with boundary layer effects and things but this appears to be a very simple model just showing what happens to air pressure and speed.

This might be an assessment ....

It appears to be a software tutorial.

Which could be an assessment ...

Tbh what i have said is pretty much the very obvious information to anyone who is studying fluids.

No point setting applied aerodynamics modelling questions if the students haven’t already comprehensively understand the phenomena of lift. The tutorial doesn’t even discuss why they are making some very broadbrush assumptions. It appears to be the type of demo so users can learn the user interface.

Coefficient of pitching moment

It would be very weird if your velocity changed from fig 2 to 3. In fig 1 velocity is high above the aerofoil, why would this flip? Think about how an aerofoil generates lift, and the principles at play.

As to what you can say, there is lots of fairly obvious characteristics you can describe from your model. But unless you are posing a specific question you can’t really just start extracting information, you need to understand if your modelling approach and assumptions are valid for the information you want to extract.

You don’t make a model then ask questions, you ask questions then decide on a model approach choosing assumptions which are valid for what you want so that you understand the limits of what what you have built and then you still need to validate accuracy and precision.

thank you

Im currently learning this only by myself. End of year i have to employ what i learnt from CFD and FEA into a reaserch project. Ive done FEA and CAD but this one has got confused with results. They gave me the tutorial to work through but no reading material to understand it. They also set question what infomation extract from the results.

Does the 3rd fig just show direction and movement of air flow?