I want to assess the drag changes of a pusher propeller when varying the spinner shape so high computational cost simulations are not a solution. I'm looking for a computationally cheap method but still capable of representing wake effects and the hub vortex effects.
Multi reference frame in OpenFOAM. It is a semi-stationary solution in which a rotationg reference frame is used to reach the regime condition.
Have a loot to the 2Dmixer tutorial.
Hi Antonio,
in order to simulate such problem and get wake and vortex effects you should use a 3D modeling, because the turbulence is strictly a 3D problem. You could start with solving the Reynolds-Averaged Navier-Stokes Equations using a turbulence model that takes into account adverse pressure gradients and separating flows. The SST k-omega model is a good start, but do not forget to use some limiter production function (i.e Menter) in order to reduce the turbulence production levels. The over-prediction of the turbulent production usually occurs in regions with large normal strain, I mean in regions with strong acceleration or deceleration (between rotor and stator domains...).
I think this approach could be considered cheap if compared with LES, DES or DNS simulations; moreover not all problems can be solved by using "cheap" computational efforts!
I hope I was helpful.
Best Regards,
Vincenzo
A series of unsteady CFD simulations have been conducted for an isolated propeller configuration at low-speed flight conditions using both a structured and an unstructured CFD method. The propeller geometry investigated is representative of a modern eight-bladed design for high-speed turboprop transport aircraft. Two typical low-speed conditions, one at zero and one at ten degrees angle of attack, were investigated and results of the two CFD methods compared with experimental data obtained from a wind tunnel test campaign. The computations were performed with the DLR FLOWer and TAU-codes respectively and employed Chimera grids, which enable the modelling of multiple rigid bodies in relative motion. The results of Euler and Navier-Stokes computations show good agreement with the available wake data measured in the wind tunnel. Additionally, a detailed analysis of the forces acting on the blades and the propeller is performed, which show a strong influence of the propeller angle of attack
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