Colloquium: Athreya Jayasimha Ballapur (AWEP)
27 januari 2020 09:30 - Locatie: Lecture Hall C, Faculty of Aerospace Engineering, Kluyverweg 1, Delft.
An Investigation of Dynamic Stall using a LBM-VLES Approach
Unsteady aerodynamic conditions have been associated with cyclic loading of turbine blades, which can have hugely detrimental effects on their operational life. This cyclic loading is resultant of the phenomenon of dynamic stall, whereby blades witness large excursions in lift compared to steady-state conditions, and sharp onset of stall.
The current project numerically investigates the effect of strongly 3D flows, particularly those observed due to blade rotation, using a LBM-VLES approach. A simple methodology is developed to achieve rotational motion while minimising computational cost. An initial mesh independence study and validation is done for quasi-2D cases. It is observed that wall-modelled turbulence has a significant impact on the numerical prediction of dynamic stall in 2D. Blade rotation is seen to further strengthen dynamic behaviour. Consequently, peak lift is increased significantly, but hysteresis in loads is reduced. Spanwise flow in separated zones is identified to be the cause for this behaviour.