tailieunhanh - Báo cáo " Analysis and identification of multi-variate random pressure fields using covariance and spectral proper transformations "

This paper will present applications of the Proper Transformations based on both cross spectral matrix and covariance matrix branches to analysis and identification of multi-variate random pressure fields. The random pressure fields are determined due to the physical measurements on some typical rectangular models in the wind tunnel tests. | VNU Journal of Science Mathematics - Physics 24 2008 209-222 Analysis and identification of multi-variate random pressure fields using covariance and spectral proper transformations Le Thai Hoa1 Yukio Tamura2 1College of Technology VNU 144 Xuan Thuy Cau Giay Hanoi Vietnam 2Wind Engineering Research Center and Faculty of Engineering Tokyo Polytechnic University Japan 1583 Iiyama Atsugi Kanagawa 243-0297 Japan Received 7 July 2008 received in revised form 12 December 2008 Abstract. This paper will present applications of the Proper Transformations based on both cross spectral matrix and covariance matrix branches to analysis and identification of multi-variate random pressure fields. The random pressure fields are determined due to the physical measurements on some typical rectangular models in the wind tunnel tests. The significant roles of the first covariance mode associated with the first principal coordinates as well as of the first spectral eigenvalue and associated spectral mode are clarified in reconstructing the random pressure fields and identifying the hidden physical phenomena inside this pressure fields. Keywords random pressure fields proper orthogonal decomposition proper transformations. 1. Introduction Aerodynamic phenomena of structures due to the atmospheric wind flows are generated by spatial distribution and correlation of random fluctuating pressure field on surface of structural section. The fluctuating pressure field can be represented as spatially-correlated multi-variate random processes. Understanding and knowledge of the random pressure field and its distribution is possible to interpret mechanisms of excitations identification and response of aerodynamic phenomena happening on structure. Due to the nature of random field however the fluctuating pressure field is considered as superposition from some causes and excitation of dominant physical phenomena. It is logical thinking to decompose the total pressure field by sums of independently .