Efficient Methods for Second Order Response Statistics to Random Excitations. Part I. Effect of Spanwise Load-Correlation on Rotor Blade Flapping.

Abstract

Second order rigid flapping response statistics of lifting rotor blades are obtained by efficient algorithms developed in this paper. These statistics make it possible to analyze the effect of a finite load correlation length on the blade response. For the particular loading (typical of turbulence excitations) and for an advance ratio small compared to unity, this effect can be concisely expressed in terms of an amplitude factor and a phase factor. In the case of a blade excited by a random vertical inflow with a spanwise correlation length of the order of the blade length, the amplitude factor shows that there may be as much as a 40% error in a solution which assumes the inflow is spatially uniform. The analytical development leading to the algorithms also illustrates how a spatial correlation method for general linear PDE with random forcing previously formulated by the author may be used in conjunction with a Ritz-Galerkin procedure.

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Document Details

Document Type
Technical Report
Publication Date
Jul 01, 1974
Accession Number
ADA034828

Entities

People

  • Frederic Wan

Organizations

  • Massachusetts Institute of Technology

Tags

Communities of Interest

  • Air Platforms
  • Weapons Technologies

DTIC Thesaurus Topics

  • Algorithms
  • Amplitude
  • Boundary Value Problems
  • Data Science
  • Differential Equations
  • Equations
  • Excitation
  • Information Science
  • Massachusetts
  • Mathematics
  • Mechanics
  • Order Statistics
  • Secondary Flow
  • Statistics
  • Steady State
  • Turbulence
  • United States

Fields of Study

  • Physics

Readers

  • Adaptive Control and Estimation with Uncertainty in Dynamic Systems.
  • Aerodynamics.
  • Fluid Dynamics.