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Title: An experimental investigation into the process of reattachment on an aerofoil undergoing a constant negative pitch motion
Author: Herring, David Geoffrey Francis
Awarding Body: University of Glasgow
Current Institution: University of Glasgow
Date of Award: 1993
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Experimental dynamic stall research has been ongoing at Glasgow University over the past ten years. The data this has furnished have led to the development of empirical predictive codes that form part of the total aerodynamic helicopter rotor blade model. This dissertation has added another complete set of data for a completely new aerofoil, indicative of an aerofoil found on the inboard section of a helicopters rotor. Additionally, through visual data analysis of the ramp down motion type across the entire dynamic stall database, it has been possible to identify the predominant features of the reattachment process. The analysis was performed on three aerofoils all having a geometric similarity with the NACA 23012 section. The tests were performed at a Reynolds number and Mach number of 1.5 million and 0.11 respectively. The tests cover pitch rates from 0.0 to 400.0 degrees per second, over the range of incidences going from +35 degrees to -5 degrees. The predominant features of the reattachment process have been identified and commented upon. Having qualified these features, they have then been mathematically modelled by extending the Beddoes empirical dynamic stall model. The inclusion of a time delay associated with the presence of the wake is shown to dramatically improve the Beddoes model in the prediction of aerodynamic loads during the reattachment process.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available