Water channel experiments of dynamic stall on Darrieus wind turbine blades

Modeling dynamic stall of a straight blade vertical axis wind turbine

“…This is mainly due to the high sensitivity of the dynamic stall to the flow conditions, such as the Reynolds number and the turbine reduced frequency which are well explained in Richter et al (2011). The attempts to analyze dynamic stall that is developed in VAWTs have been mainly based on the experimental data and this is due to the mathematical modeling difficulties (Fraunie et al, 1986;Laneville and Vittecoq, 1986). In recent years, the advancement of experimental equipment has allowed flow field measurements of the VAWTs to be made using such techniques as particle image velocimeter (PIV) techniques (Ferreira et al, 2009;Fujisawa and Shibuya, 2001).…”

Turbulence modeling of deep dynamic stall at relatively low Reynolds number

“…However, the aerodynamics of the HAWTs under the conditions such as yawing is very similar to what occurs when the blade performs a harmonic pitching, as investigated in this paper, in terms of the formation of the leading edge vortex, vortex shedding, etc., due to the constant changing in the angle of attack (AOA) perceived by the turbine blades (Hansen and Butterfield, 1993). For VAWTs, in particular the Darrieus type, or lift-driven type turbine, the flow perceived by the turbine blade also varies cyclically in both direction and magnitude leading to almost constant occurrences of the dynamic stall in the operation of these types of wind turbines (Fraunie et al, 1986). In addition to the aerodynamic performance, the dynamic stall is also a substantial source of the structural vibration pertinent to the fatigue life of the turbine (McLaren et al, in press).…”

Simulating variable pitch crossflow water turbines: A coupled unsteady ONERA-EDLIN model and streamtube model

“…They are respectively the induced velocity at quarter chord, and the derivative of this induced velocity relatively to the half-chord variable. This is written in Equations (10) and (11).…”