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Correlation Structures of Pressure Field and Integrated Forces on Oscillating Prism in Turbulent Flows
AbstractThis study sought to illuminate the turbulence-induced changes in the aerodynamic correlation structure on a stationary/oscillating rectangular prism. A forced-vibration system was used with a model instrumented with 66 pressure transducers. The study included the effects of the turbulence intensity, turbulence integral scale, and structural motion on the spanwise and streamwise correlation (or coherence) of integrated aerodynamic quantities (lift force or torsional moment) and pressures. These effects are discussed based on the stationary model tests, the oscillating model tests in the low to the high reduced velocity ranges, which are characterized as three different aerodynamic regimes. In general, the turbulence scale effects are more significant than those of the turbulence intensity. Larger turbulence scale usually leads to larger spanwise correlation of aerodynamic quantities on stationary models, but the results of the oscillating model tests in the low reduced velocity range indicate a reversal of this trend. In the high reduced velocity range, the self-excited force exhibited correlation coefficients greater than 0.95 for every incident flow in the entire spanwise separation range considered (2.4 times the deck width), which supports the assumption common in analytical modeling of fully correlated self-excited forces. Typically, the lift force correlation is larger than that of the torsional moment. The self-excited force correlation values were far larger than those of any velocity components and significantly larger than those of the buffeting force. Spanwise correlation of the buffeting force showed exceptional similarity between stationary and oscillating model tests. The spanwise correlation of the total wind-induced force (a combination of the self-excited and buffeting forces) has a value between those of the self-excited and buffeting cases, individually.
Correlation Structures of Pressure Field and Integrated Forces on Oscillating Prism in Turbulent Flows
AbstractThis study sought to illuminate the turbulence-induced changes in the aerodynamic correlation structure on a stationary/oscillating rectangular prism. A forced-vibration system was used with a model instrumented with 66 pressure transducers. The study included the effects of the turbulence intensity, turbulence integral scale, and structural motion on the spanwise and streamwise correlation (or coherence) of integrated aerodynamic quantities (lift force or torsional moment) and pressures. These effects are discussed based on the stationary model tests, the oscillating model tests in the low to the high reduced velocity ranges, which are characterized as three different aerodynamic regimes. In general, the turbulence scale effects are more significant than those of the turbulence intensity. Larger turbulence scale usually leads to larger spanwise correlation of aerodynamic quantities on stationary models, but the results of the oscillating model tests in the low reduced velocity range indicate a reversal of this trend. In the high reduced velocity range, the self-excited force exhibited correlation coefficients greater than 0.95 for every incident flow in the entire spanwise separation range considered (2.4 times the deck width), which supports the assumption common in analytical modeling of fully correlated self-excited forces. Typically, the lift force correlation is larger than that of the torsional moment. The self-excited force correlation values were far larger than those of any velocity components and significantly larger than those of the buffeting force. Spanwise correlation of the buffeting force showed exceptional similarity between stationary and oscillating model tests. The spanwise correlation of the total wind-induced force (a combination of the self-excited and buffeting forces) has a value between those of the self-excited and buffeting cases, individually.
Correlation Structures of Pressure Field and Integrated Forces on Oscillating Prism in Turbulent Flows
Kareem, Ahsan (Autor:in) / Wu, Teng / Haan, Fred L
2016
Aufsatz (Zeitschrift)
Englisch
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