Parallel Blade-vortex Interaction Research Articles

Parallel Blade-Vortex Interactions: An Experimental Study and Comparison with Computations

Parallel Blade-Vortex Interactions: An Experimental Study and Comparison with Computations

Role of secondary vorticity in parallel blade-vortex interactions

This work incorporates viscous effects and the no-slip criterion in analyzing the blade-vortex interaction (BVI) problem with the discrete vortex model. Most previous BVI investigations have been purely potential in nature, so that only the zero normal velocity criterion was imposed on the body surface. In the current work, a boundary-layer code that predicts separation on an infinite flat plate under the influence of a line vortex is adapted to the BVI problem, so that it may be used with a semi-infinite plate in a flowfleld composed of a freestream and numerous discrete vortices. Although a steady, laminar boundary-layer assumption is used to predict separation, the kinematics resulting from the interaction of the primary vortex and the shed vorticity are in agreement with previous observations.

An examination of vortex convection effects during blade-vortex interaction

AbstractThe experimental results of a parallel Blade-Vortex Interaction (BVI) study are presented. The quality of all pressure data reflects improvements in the Glasgow University BVI facility and in the method of reducing and presenting data. Pressure histories clearly track the passage of a vortex-associated disturbance across the aerofoil. Tracking this disturbance permits an examination of vortex convection velocities, and also allows for a correlation between vortex trailing edge passage and force and moment perturbations.

An experimental investigation of the oblique blade-vortex interaction

AbstractThe experimental results of an oblique Blade-Vortex Interaction (BVI) study are presented. The quality of all pressure data reflects improvements in the Glasgow University BVI facility and in the method of reducing and presenting data. The data collected during oblique interactions is found qualitatively and quantitatively similar to that collected in corresponding parallel interactions, for interactions within ± 30° of parallel. Details of the pressure data are examined in the light of understanding gained from parallel BVI experimentation. The study highlights the effects of three dimensional flow interactions not accounted for in the nondimensionalisation traditionally utilised in the analysis of parallel blade-vortex interactions.

Incremental force and moment coefficients for a parallel blade-vortex interaction

Blade-vortex interactions occur in helicopter rotors when a rotor blade passes close to or through a tip vortex trailing from the same or another blade. An unsteady, parallel blade-vortex interaction model was developed using a discrete free-vortex method and classical potential flow theory. The tip vortex was modeled by a simple vortex and, for a close encounter, by a cluster of vortices.

Investigation of the parallel blade-vortex interaction at low speed

Low-speed wind-tufnel tests were conducted to investigate the parallels blade-vortex interaction. Flow-visualisation tests of vortex generation performed before the pressure tests showed that