Upwind Navier-Stokes solutions for leading-edge vortex flows

1989 ◽  
Author(s):  
C.-H. HSU ◽  
C. LIU
Keyword(s):  
Leading Edge ◽  
Navier Stokes ◽  
Vortex Flows ◽  
Leading Edge Vortex ◽  
Edge Vortex

scholarly journals Coriolis effect and the attachment of the leading edge vortex

2017 ◽  
Vol 820 ◽  
pp. 312-340 ◽  
Author(s):  
T. Jardin
Keyword(s):  
Stokes Equations ◽  
Leading Edge ◽  
Navier Stokes ◽  
Coriolis Effect ◽  
Viscous Effects ◽  
Navier Stokes Equations ◽  
Leading Edge Vortex ◽  
Edge Vortex ◽  
Vorticity Transport ◽  
Rotating Wing

The role of the Coriolis effect on the attachment of the leading edge vortex (LEV) is investigated. Toward that end, the Navier–Stokes equations are solved in the non-inertial reference frame of a high angle of attack $\unicode[STIX]{x1D6FC}$ rotating wing with the Coriolis term being artificially tuned. Reynolds numbers in the range $Re\in [100;750]$ are considered to identify the interplay between Coriolis and viscous effects. Similarly, artificial tuning of the centrifugal term is achieved to identify the interplay between Coriolis and centrifugal effects. It is shown that (i) the Coriolis effect is the key element in LEV stability for $Re>200$, (ii) viscous effects are the key element for $Re<200$ and (iii) centrifugal effects have a marginal role. The Coriolis effect is found to promote spanwise flow in the core and behind the LEV, which is known to promote outboard vorticity transport and presumably contributes to stabilizing the aft boundary layer. These mechanisms of LEV stabilization have increased authority as $\unicode[STIX]{x1D6FC}$ decreases.

Simulation of leading-edge vortex flows

1990 ◽  
Vol 1 (6) ◽  
pp. 379-390 ◽  
Author(s):  
C.-H. Hsu ◽  
C. H. Liu
Keyword(s):  
Leading Edge ◽  
Vortex Flows ◽  
Leading Edge Vortex ◽  
Edge Vortex

Computation and visualization of leading edge vortex flows

1990 ◽  
Vol 1 (2-4) ◽  
pp. 341-348
Author(s):  
E.M. Murman ◽  
T.M. Becker ◽  
D. Darmofal
Keyword(s):  
Leading Edge ◽  
Vortex Flows ◽  
Leading Edge Vortex ◽  
Edge Vortex

Leading Edge Vortex Development on a Pitch-Up Airfoil

2013 ◽  
Author(s):  
Kyle Hord ◽  
Yongsheng Lian
Keyword(s):  
Stokes Equations ◽  
Leading Edge ◽  
Navier Stokes ◽  
Vortex Generation ◽  
Navier Stokes Equations ◽  
Leading Edge Vortex ◽  
Overlapping Grids ◽  
Wing Motion ◽  
Circulatory Effects ◽  
Edge Vortex

The dynamics of leading edge vortex (LEV) on an airfoil due to pitch-up motion is investigated using computational fluid dynamics techniques to solve the Navier-Stokes equations on composite overlapping grids. The objectives are to (1) quantify the contribution of circulatory effects caused by vortex development, and non-circulatory effects due to rotational acceleration of the pitch up, and (2) measure the growth rate of the LEV. The pitch-up angle is from 0 to 45 degrees, an approximation of the wing motion of a perching flyer, and the Reynolds number is approximately 500. Previous studies have investigated vortex development on pitch-up airfoils, and found the development of the LEV varies with pitch rate; however this phenomenon has never been quantified. In this study we will look at how vortex generation and diffusion at lower Reynolds numbers affect circulatory forces on the wing. The Q-criterion method is used to identify and isolate vortex structures from shear vorticity in order to numerically calculate the circulation in the computation domain caused by the LEV. The calculated circulation due to vortices will then be compared to the lift force by the pitch-up motion to obtain a better understanding of the contribution to lift exclusively by vortex generation. Previous studies involving pitch-up maneuvers have hypothesized that the increase of lift with pitch rate may be due to virtual mass effects, also known as noncirculatory forces. However this increase in lift has not been quantified. Using the noncirculatory component of Theodorsen’s theory, the lift forces can be broken into parts caused by the rotation of the wing, and the aerodynamic effects. Results have shown that noncirculatory forces only contribute 10–20% of the lifting force and the remaining is due to the LEV. It was also found that the LEV growth is time dependent and not angle dependent; however the circulation strength of the LEV is a function of pitch rate. Thus the higher pitch rates have smaller, yet stronger LEVs.

Numerical simulation of leading-edge vortex flows

AIAA Journal ◽  
1986 ◽  
Vol 24 (2) ◽  
pp. 237-245 ◽  
Author(s):  
Donald P. Rizzetta ◽  
Joseph S. Shang
Keyword(s):  
Numerical Simulation ◽  
Leading Edge ◽  
Vortex Flows ◽  
Leading Edge Vortex ◽  
Edge Vortex
Sign in / Sign up

Export Citation Format

Share Document