Low Reynolds number response of a symmetric airfoil to viscous vortical gusts

The response of a NACA0012 airfoil impacted by viscous vortical gusts at low Reynolds numbers is investigated performing Direct Numerical Simulations of the two-dimensional incompressible flow. This database contains the time history of the aerodynamic force coefficients of the airfoil during the interaction with the vortical gust. The airfoil, set at a fixed angle of attack alpha, is impacted by Taylor/Lamb-Oseen vortical gust, which are characterized by a diameter D, a intensity v0m, and a vertical separation h. Direct Numerical Simulations are run for a range of values for the angle of attack, the size and intensity of the vortical gust, and the vertical separations. All simulations are run at a fixed Reynolds number Re=1000, based on the airfoil chord c and the free-stream velocity U∞.

More details on the database and the corresponding simulations can be found in Martínez-Muriel & Flores (2020), Analysis of vortical gust impact on airfoils at low Reynolds number, J. Fluids and Struct, 99. 

Contents
The database consist on a single ASCII file for each case. After a short, self-explanatory header, each file has 7 columns with the following data: 

time, t U∞/c

cl: lift coefficient, cl

cd: drag coefficient, cd

cm: coefficient of moments with respect to c/4, cm

dcl:  perturbation of cl with respect to steady state value, ∆cl 

dcd:  perturbation of cd with respect to steady state value, ∆cd 

dcm:  perturbation of cm with respect to steady state value, ∆cm 

Reference time (t=0) is taken as the time at which the center of the vortical gust reaches the position of the leading edge of the airfoil (if advected at a velocity U∞). 

Nomenclature 
The names of the files will follow the acronym t_AaYyDdVv.txt, where the lowecase letters are placeholders for: 

 t 
 Type of vortical gust
 T: Taylor, LO: Lamb-Oseen

 a 
 Angle of attack 
 α = [+8,0,-8] deg

 y 
 Initial vertical position of the centre of the vortex
 h/c = [0,0.5,1]

 d 
 Diameter of the core of the vortex 
 D/c = [0.5,1,2]

 v 
 Circumferential velocity 
 v0m/U∞ = [0.1,0.3,1]