Application of multi-point correlation techniques to aerodynamic flows
Conference Paper
Overview
Overview
abstract
1994 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. Two multi-point correlation techniques, linear stochastic estimation (LSE) and proper orthogonal decomposition (POD), are used to develop an under-standing of the spatial evolution of the transitional and turbulent flow over a 45 swept wing. LSE is used to estimate instantaneous hot-film time histories in the crossflow and streamwise directions given the two-point correlation tensor and at least one instantaneous hot-film reference signal. The estimated instantaneous data are then compared to the original measured instants neous data and quantified by a root mean square recovery ratio. An originally measured crossflow field of 13 hot-film channels is recovered to within 95% and 98% by estimates using only 2 and 3 reference signals, respectively. The POD is also applied to these surface hot-film data bases. The eigenfunctions from the crossflow solution display the periodicity found in the flow field. The eigenfunctions extracted in the streamwise direction are determined as the flow transitions to turbulence. A distinct transfer of energy is demonstrated by the spatial evolution of the second and third modes. The third mode dominates in the transition region and resembles wave-packet spatial behavior. As the turbulence region is approached, the third POD mode decays and mode 2 begins and continues to grow until the end of the resolved domain.
