角柱風上面に作用する風圧変動に関する研究

Abstract

The relation between pressure fluctuations on windward faces of square prisms andvelocity fluctuations in the approaching flow was investigated by a wind tunnel experiment.Cross-correlation and coherence between the velocity fluctuations and the pressure fluctua-tions in the experiment showed that the most pressure fluctuations were linearly related tothe velocity fluctuations in the approaching flow. The admittance of the velocity fluctua-tions to the pressure fluctuations was expressed as a function of reduced frequency n.D/Uwhere n is frequency, D the length of the side of the prism and U the mean velocity.Normalized cospectra of the pressure fluctuations were greater than those of the velocityfluctuations in the measured frequency range. The power spectra of the drag fluctuationsof flat plates were computed from those of the velocity fluctuations by the above admittancetogether with the normalized cospectrum of the pressure fluctuations, disregarding thepressure fluctuations on the leeward face.