Authors: Kyle Hord; Yongsheng Lian
Addresses: Department of Mechanical Engineering, University of Louisville, Louisville, KY, USA ' Department of Mechanical Engineering, University of Louisville, Louisville, KY, USA
Abstract: The development of the lift generated by a leading edge vortex (LEV) across a flat plate experiencing a pitch-up motion is investigated to understand the LEV's influence on lift generation. The flow field around the pitch-up plate is simulated by solving the Navier-Stokes equations on composite overlapping grids. The pitch-up angle was from 0 to 45 degrees and the Reynolds number was 500. The Q-criterion method was used to isolate vortex structures from shear layer vortices in order to assess the circulation of the LEV. The calculated circulation due to LEV was then compared to the computed lift from simulation for a better understanding of the effect of the LEV on lift generation. Using the non-circulatory component of Theodorsen's theory, we separate the total lift into lift due to the plate rotation (non-circulatory lift) and lift due to aerodynamic effects (circulatory lift). Our results showed that the non-circulatory force only contributes 10-20% of the total lift and the remaining is due to the LEV. We also found that the LEV growth mainly depends on time but not the angle of attack. However, the circulation strength of the LEV depends on the pitch rate.
Keywords: computational fluid dynamics; CFD; leading edge vortex; pitch-up airfoils; LEV; pitching wing; lift generation; simulation; Navier-Stokes equation; vortex structures; shear layer vortices; plate rotation; non-circulatory lift; aerodynamics; circulatory lift; angle of attack; time; circulation strength; pitch rate.
International Journal of Aerodynamics, 2015 Vol.5 No.1, pp.69 - 81
Available online: 08 Feb 2016 *Full-text access for editors Access for subscribers Free access Comment on this article