low Re we define as foils with Re < 150'000:
case A: no microturbulence as in windtunnels. generally use flat profiles with a short section of negative pressure gradient at LE. tripping and separation avoidance devices are usually a must for Cl>0.5. e.g. Chang vortexgenerators at LE and oblique...
hello,
in our own work on wingtips at present we suggest the following categories of vortex wakes:
1. Munk-type vortex wakes; coming from wings with linear interference of spanload and trailing vortex wakes. comprising planar and non-planar wings
2. Non-Munk-types; caused by outer part of wing...
hello,
in any case the actual Renolds number is very important. why? because for Re > 200'000 conventional turbulant B.L. tricks work, below we ave to use tricks curing laminar separation or recirculations. for the latter case refer to the classic book Peter Chang "Flow Separation". a...
avoiding separation in positive pressure gradient is possible by injecting more kinetic energy into the boundary layer. for laminar B.L. this is far from easy and there are other tricks. see www.winggrid.ch keyword oblique grooves. this arrangement allows Cl-values up to 4 at Re down to 10'000.
