Accession Number : ADA258019


Title :   A Computational and Experimental Investigation of the Propulsive and Lifting Characteristics of Oscillating Airfoils and Airfoil Combinations in Incompressible Flow


Descriptive Note : Master's thesis


Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA


Personal Author(s) : Neace, Kerry S


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a258019.pdf


Report Date : Sep 1992


Pagination or Media Count : 125


Abstract : Computational and experimental methods have been used to systematically study one and two airfoils undergoing unsteady motion. First, a single airfoil analysis was done with the modified computer code, U2DIIF. Thrust, efficiency, and phase relationships were computed and compared to existing theoretical results. Furthermore, to help understand the dynamic stall process, relationships were developed between steady and quasi-steady pressure distributions for an airfoil undergoing a ramp motion. Next, an unsteady analysis for two airfoils was done with the modified computer code, USPOTF2. Again, thrust and efficiencies for interfering, harmonically oscillating airfoils were computed and compared to existing theoretical results. Furthermore, an analysis was completed on the effects of a harmonically oscillating airfoil on the pressure gradient of a stationary airfoil. Finally, flow visualization experiments were conducted using a low speed smoke tunnel at the Naval Postgraduate School (NPS). This experiment demonstrated the effects of a thrust producing, oscillating airfoil on the formation of the wake vortices. Furthermore, a flow visualization experiment was conducted in the NPS low speed wind tunnel, which demonstrated the beneficial influence of a secondary airfoil oscillating in the vicinity of a stationary airfoil at high angle-of-attack.


Descriptors :   *PRESSURE GRADIENTS , *EFFICIENCY , *FLOW VISUALIZATION , *AIRFOILS , *VORTICES , *PHASE , *WAKE , *THRUST , *RAMPS , COMPUTERS , ANGLE OF ATTACK , DYNAMICS , LIFT , HIGH ANGLES , WIND TUNNELS , SMOKE , MOTION


Subject Categories : Aerodynamics
      Military Aircraft Operations
      Flight Control and Instrumentation
      Military Operations, Strategy and Tactics


Distribution Statement : APPROVED FOR PUBLIC RELEASE