Prediction of the Steady State Dynamic Behavior of an Elastically Supported Rigid Plate Subjected to a Steady Uniform Airflow

Abstract

The steady state dynamic behavior of an autonomous nonconservative system is investigated both numerically and experimentally. The system consists of an elastically supported rigid plate and is subjected to a uniform steady airflow. The plate is allowed to execute large rotational oscillations. Therefore, the flow separates and reattaches as the plate oscillates. Modeling the motion-dependent fluid forces using the unsteady Navier-Stokes equations coupled with the structural equations is a very formidable task and requires an immense amount of computations. An alternative approach to model the solid-fluid interaction is presented. The model is improved based on the measured time histories of the plate motion. The refined mathematical model is used to predict the steady state frequency of the plate vibration. Another objective of the current study is to develop empirical equations to predict the critical flow speed that initiates the plate vibration as well as the self-excited frequency of the plate oscillations. The equations include all the relevant parameters of the system. The developed equations are then verified experimentally. A good correlation between the predicted and the tested results is achieved.