Colloquium: Pieter van Pelt (FPP)
27 september 2019 14:00 - Locatie: Lecture Room D, Faculty of Aerospace Engineering, Kluyverweg 1, Delft.
Genesis of the Kutta condition - An empirical study of the transient flow which produces the Kutta condition flow-field
The Kutta condition is a boundary condition applied at a wing’s trailing edge (TE), which enables the calculation of the fluid-dynamic lift produced by a wing in potential flow. This condition is a stable equilibrium resulting from a transient flow. The main question of this research is: how is the Kutta condition flow-field created when a wing is brought in motion from rest? This is investigated using an experimental apparatus, in which a wing model is accelerated from rest and the transient TE flow is analysed using high-speed Particle Image Velocimetry techniques.
Initially, fluid moves from the airfoil’s pressure side, along the TE, towards the suction side, and a boundary layer is created. Then, boundary layer stagnation occurs, a vortex separates from the TE, and a transformation in the presence and locations of stagnation/separation occurs. The observed process confirms classical theories which describe the creation of the Kutta condition flow-field.