[jeongyun]

I found this simple tool can calculate and visualize ground effect of an airfoil. Though with some limitations.

JavaFoil

Theoretical Background

JavaFoil is a relatively simple program, which uses several traditional methods for airfoil analysis. The following two methods build the backbone of the program:

The potential flow analysis is done with a higher order panel method (linear varying vorticity distribution). Taking a set of airfoil coordinates, it calculates the local, inviscid flow velocity along the surface of the airfoil for any desired angle of attack.
The boundary layer analysis module steps along the upper and the lower surfaces of the airfoil, starting at the stagnation point. It solves a set of differential equations to find the various boundary layer parameters. It is a so called integral method. The equations and criteria for transition and separation are based on the procedures described by Eppler [13, 14, 15]. Compared with CalcFoil, this module has been completely rewritten and cleaned up.

Limitations

As said above, JavaFoil is a relatively simple program, with some limitations. As with all engineering computer codes, it is up to the user to judge and to decide how far he wants to trust a program. Because JavaFoil does not model laminar separation bubbles and flow separation, the results will be incorrect if either of these occur. Flow separation, as it occurs at stall, is modeled to some extent by empirical corrections, so that maximum lift can be predicted for "conventional" airfoils. If you analyze an airfoil beyond stall, the results will be quite inaccurate. It is questionable, whether a two dimensional analysis method can be used at all in this regime, as the flow field beyond stall is fully three dimensional with spanwise flow and strong vortices.

Wing in Ground Proximity