Carlos Pimentel's blog

Go to the first part:  On innovation and other hoaxes: a true story at university (Part 1) Most real aerodynamicists, even computationalists, know the typical pressure coefficient (cp) distribution for an airfoil (with positive AoA) in the pre-stall region, where cp tends to increase from the suction side (top) towards the leading edge (LE), typically with a negative peak value. On the other hand, at the frontal stagnation point, such a value must be equal to 1 (for the incompressible case), which no longer coincides with the geometric frontal point of the airfoil, since it is naturally shifted backwards due to its inclination. Obviously, a zero value of cp must be located in such a curved region, i.e. close to the geometric frontal point (see Fig. 1). But what happens if instead of an airfoil we use an "infinitely thin" flat plate? Yes, in the limit of thickness equal to zero, cp must be equal to the difference between the upper and lower side cp's , which have a diff...

Go to the first part:  On innovation and other hoaxes: a true story at university (Part 1) After numerically understanding the effects of adding lateral wakes to flat plates, especially for low aspect ratio (LAR) configurations, a more complex steady-state scheme was proposed by my advisor. It consists of including internal detached wakes to account for flow separation, similar to Gersten's vortex model (see Fig. 1, up). Therefore, I first explored a simpler model, the lifting line method (based on the Lifting Line Theory or LLT), by including detached horseshoe vortices instead of bounded vortex rings as in the VLM. Such a scheme is not new, in fact some authors have proposed similar approaches in the past to account for flow separation in the context of Potential Flow Theory (PFT), improving the obtained results by far. Furthermore, I found that in the 90s, Prof. D.A. Durston of NASA published a similar vortex model ( LinAir code) to account for flow separation by including trai...