Aerodynamic data collection procedure

• US 4,372,157 A
• Filed: 04/07/1981
• Issued: 02/08/1983
• Est. Priority Date: 04/07/1981
• Status: Expired due to Fees

• Current Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Rothrock, Mark D., Caruthers, John E., Riffel, Ronald E., Jay, Robert L.
• Primary Examiner(s): Kazenske, Edward R.
• Assistant Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US06/251,907
• Time in Patent Office: 672 Days
• Field of Search: 73/147, 73/455, 73/456, 73/583, 29/156.8 B
• US Class Current: 73/147
• CPC Class Codes: G01M 9/06 Measuring arrangements specially adapted for aerodynamic testing

Abstract

An improved procedure for collecting experimental data reflecting the behavior of a time varying aerodynamic parameter at an airfoil in a cascade of airfoils vibrating harmonically in a fluid stream including the steps of vibrating the center airfoil of the cascade at a selected frequency and amplitude while each of the other airfoils is held rigid, measuring the time varying parameter at the center airfoil and expressing it as a function of the position of the center airfoil in its vibratory cycle, vibrating each of the other airfoils in turn at the selected frequency and any amplitude while maintaining all the remaining airfoils rigid, measuring the time varying parameter at the center airfoil for each individual airfoil vibration and expressing the measurement as a function of the position of the individual vibrating airfoil, expressing the position of each individual vibrating airfoil as a function of the position of the center airfoil, and combining the time varying parameter expressions and position expressions to reflect the time varying parameter behavior when all the airfoils vibrate harmonically at the selected frequency and any amplitude.

Claims

1. A procedure for collecting experimental data reflecting the behavior of a time varying aerodynamic parameter at an airfoil in a cascade of harmonically vibrating airfoils comprising the steps of placing said cascade of airfoils in a wind tunnel, subjecting said cascade to a continuous steady state fluid stream in said wind tunnel, vibrating a center airfoil of said cascade at a selected frequency and a selected amplitude while all of the other of said airfoils in said cascade are held rigid, measuring a time varying parameter at said center airfoil during vibration thereof, vibrating in turn and in said fluid stream each of said other airfoils at said selected frequency but at an arbitrarily selected amplitude which all of the remaining airfoils in said cascade including said center airfoil are held rigid, measuring said time varying parameter at said center airfoil during vibration of each individual one of said airfoils, and combining all of said time varying parameter measurements to reflect the behavior of said time varying parameter at said center airfoil when all of said airfoils in said cascade including said center airfoil are vibrated harmonically at said selected frequency and at the same amplitude.

2. A procedure for collecting experimental data reflecting the behavior of a time varying aerodynamic parameter at an airfoil in a cascade of harmonically vibrating airfoils comprising the steps of placing said cascade of airfoils in a wind tunnel, subjecting said cascade to a continuous steady state fluid stream in said wind tunnel, vibrating a center airfoil of said cascade at a selected frequency and a selected amplitude while all of the other of said airfoils in said cascade are held rigid, measuring a time varying parameter at said center airfoil during vibration thereof and expressing said measurement as a function of the position of said center airfoil in its vibratory cycle, vibrating in turn and in said fluid stream each of said other airfoils at said selected frequency but at an arbitrarily selected amplitude while all of the remaining airfoils in said cascade including said center airfoil are held rigid, measuring said time varying parameter at said center airfoil during vibration of each individual one of said airfoils and expressing each individual measurement as a function of the position of the corresponding one of said individually vibrating airfoils in its vibratory cycle, expressing the position of each of said individually vibrating airfoils in its vibratory cycle as a function of the position of said center airfoil in its vibratory cycle, and combining all of said time varying parameter measurements expressed as functions of individually vibrating airfoil positions and all of said individual airfoil positions expressed as functions of the position of said center airfoil in its vibratory cycle to reflect the behavior of said time varying parameter at said center airfoil when all of said airfoils in said cascade including said center airfoil are vibrated harmonically at said selected frequency and at the same amplitude.

3. The improved procedure recited in claim 2 wherein the time varying parameter being measured is the fluid pressure at a surface of said airfoil.