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 v_0m, 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, c_l
• cd: drag coefficient, c_d
• cm: coefficient of moments with respect to c/4, c_m
• dcl:  perturbation of c_l with respect to steady state value, ∆c_l 
• dcd:  perturbation of c_d with respect to steady state value, ∆c_d 
• dcm:  perturbation of c_m with respect to steady state value, ∆c_m 

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: