Accession Number : ADA563389


Title :   Global Pressure and Temperature Surface Measurements on a NACA 0012 Airfoil in Oscillatory Compressible Flow at Low Reduced Frequencies


Descriptive Note : Master's thesis


Corporate Author : OHIO STATE UNIV COLUMBUS


Personal Author(s) : Jensen, Christopher D


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a563389.pdf


Report Date : Jan 2012


Pagination or Media Count : 146


Abstract : A co-axial contra-rotating helicopter in forward flight has stall mechanisms that are intrinsically different from those on a traditional helicopter. Traditional helicopters need a cyclic pitch mechanism to balance the rotor lift about each rotation, which leads to dynamic stall from the rapid oscillations in pitch. Co-axial contra-rotating helicopters, which have a fixed pitch about each cycle, encounter a sinusoidal oscillation in Mach number with the mean velocity seen as the rotational velocity while the half amplitude is equal to the forward flight speed. The fluid dynamic mechanism limiting the forward flight speed is entirely different from that of traditional dynamic stall studies. This work sets out to design, create, and study the application of an oscillatory compressible flow field on a NACA 0012 airfoil in order to experimentally model this flow situation.


Descriptors :   *AIRFOILS , *COMPRESSIBLE FLOW , ANGLE OF ATTACK , CALIBRATION , FLIGHT SPEEDS , FLOW FIELDS , FLUID DYNAMICS , HELICOPTERS , IMAGE REGISTRATION , LEVEL FLIGHT , MACH NUMBER , OSCILLATION , PARTICLE IMAGE VELOCIMETRY , WIND TUNNELS


Subject Categories : Aircraft
      Fluid Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE