Originally Posted by Dickeroo
I would love to know what the people on the VortexCell2050 project have learned about the use of the trapped vortex. I can't imagine that they would be pursuing this idea if it wasn't going to be productive for them.
Anyone know how to find out more info?
The project report was completed and issued in 2008 (I've referenced this report before in this thread): http://ltces.dem.ist.utl.pt/lxlaser/...ers/11.3_4.pdf
Here's a quote from the Conclusions in the report (Section 5)
From the showed results the following conclusions can be draw. Passive TVC (Trapped Vortex Cell) flow control is not able to control the flow separation. The vortex is not confined in the cavity and vortex shedding is present decreasing the aerodynamic characteristics of the original airfoil. Active TVC flow control is able to control the flow separation, for limited values of the blowing coefficient full reattachment has been obtained.[/U]
So what they found was that without 'active vortex control' it was impossible to trap a stable vortex in the step/cell. The vortex could not be prevented from shedding which degraded performance compared to the same airfoil without the step/cell.
By adding complex active suction/blowing of the step/cell (three suction nozzles and one blower in the cell itself) they were able to maintain a stable trapped vortex in certain conditions and this did show positive results.
The test results are discussed in more detail in the 'results and discussions' section (section 4). Attached is a PIV image taken from section 4 which clearly shows how the vortex step/cell results causes full separation of the airflow downstream (i.e. a stall). With active control of the vortex cell they were able to prevent this separation but they don't have a good image showing that in the report.