Over the past decade or so various faculty and students at the Naval Postgraduate School have worked on the development of several unsteady potential-flow solvers, commonly referred to as panel methods. These panel methods offer the distinct advantage of being very computationally inexpensive, so much so that the programs can run essentially real-time on PC's and graphics workstations. Over the past few years I have developed Graphical User Interfaces (GUIs) for the single and multi-element panel codes. The addition of the GUI not only provided a visually enlightening presentation of the unsteady flowfields, but it provided a mechanism for real-time interaction with the computation. The resulting software suite is something like a virtual wind tunnel, allowing users to probe the flowfield in much the same that an experimentalist would in a wind or water tunnel.

Unsteady Wake Visualization: The original incentive for developing the software package was the visualization of the unsteady wake generation and evolution. These panel methods incorporate a nonlinear wake model that may accurately simulate wake rollup, vorticity stretching and merging, and other wake phenomenon. Click on the circle-i icon for more information and a JavaScript animation.
Wake Dynamics in Ground Effect: The unsteady flow about two independent airfoils may be predicted by a multiple-element version of the panel code. One very interesting application is the investigation of an airfoil in ground effect. By moving a second airfoil symmetrically in a mirror fashion, a symmetry-plane between the two airfoils is defined which simulates a ground plane. We see birds and insects fly close to the ground often and, as it turns out, they do this because both their thrust and their their propulsive efficiency are increased. Click on the circle-i icon for more information and a JavaScript animation.
Wake Interference Effects: Perhaps a more interesting application of the multi-airfoil code is a case where the wake shed from one airfoil directly impinges the other airfoil. The simulation illustrated here is of a classic flapping-wing propulsion device called the Schmidt Wave-Propellor. More details of the design principles and performance of the wave propellor can be found by clicking on the image to the right or the circle-i icon.