Accession Number : ADA302254

Title :   Comparison of Two Shock-Capturing Methods for Calculation of Transonic Airfoil Flutter.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH

Personal Author(s) : Buxton, Bradley J.

PDF Url : ADA302254

Report Date : DEC 1995

Pagination or Media Count : 108

Abstract : The flutter of a pitch-and-plunge airfoil (PAPA) in transonic flow is simulated using two shock-capturing methods. Each method solves a coupled system of equations involving the unsteady Euler equations and a two-degree-of-freedom structural model. The first method, TVDntiAE, uses an explicit Total-Variation-Diminishing (TVD) algorithm to compute the flowfield for a 2-D airfoil. The second method, ENS3DAE, uses an implicit Beam-Warming approach to compute the flowfleld on a 3-D rectangular wing while enforcing 2-D flow. Results of the schemes are compared with each other and against limited published data to extend the validation of the software to unsteady fluid/structure interactions. Results are compared for three airfoil configurations: (1) static; (2) forced oscillation; and (3) PAPA. Computation of flutter points is of special interest. ENS3DAE predicts a flutter onset speed for the NACA 64A-006 airfoil at M=0.87 that is 1% greater than the value predicted by TVDntiAE and 2% smaller than the published data. Variations in model predictions most likely due to dissipation-model differences and grid and time-step sensitivities are evaluated. (AN)

Descriptors :   *FLUTTER, *TRANSONIC FLOW, *TRANSONIC AIRFOILS, MATHEMATICAL MODELS, ALGORITHMS, STEADY STATE, PITCH(MOTION), TIME DEPENDENCE, VALIDATION, AERODYNAMIC STABILITY, STRUCTURAL ANALYSIS, COMPARISON, SHOCK WAVES, AIR FLOW, ACCURACY, THESES, COMPUTATIONAL FLUID DYNAMICS, ANGLE OF ATTACK, DEGREES OF FREEDOM, AEROELASTICITY, FLOW FIELDS, AERODYNAMIC LOADING, MACH NUMBER, TWO DIMENSIONAL FLOW, UNSTEADY FLOW, INVISCID FLOW, INSTABILITY, PRESSURE DISTRIBUTION, AERODYNAMIC LIFT, GAS SURFACE INTERACTIONS, RUNGE KUTTA METHOD, WING TIPS, TRANSONIC CHARACTERISTICS.

Subject Categories : Aerodynamics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE