Contribution
Numerical study of installed distributed Propellers using body-force model on cartesian grids
* Presenting author
Abstract:
In this study, the installation effect of distributed propellers is evaluated. Five of ten propellers installed on an aircraft with strut-braced wings are simulated with a volume-resolving finite differences approach. The body forces of the propeller are calculated using blade-element theory reacting on the actual flow. The non-linear Navier-Stokes equations in perturbed form provide the flow around the aircraft geometry as well as the propeller wake. The simulations, performed with DLR’s inhouse finite differences code PIANO, utilize automatically generated octree Cartesian grids in combination with an immersed boundary method (IBM) with a sharp interface.To evaluate the installation effect, a computation with isolated propellers (not installed) is compared against the installed computation.These computations deal with the installation effect on the source, i.e. the change in flow at the propeller blade position due to the change of circulation around the wing, as well as the wake- wing interaction.The computations are carried out on 1400 CPUs with a domain size of 50m x 60m x 20m containing 150 million points. One revolution of a propeller takes roughly 9 hours and therefore costs 12 kCPUh.The method is a LES with propellers modelled as body forces informed by blade element theory.