A.O.Borisyuk Experimental study of the wall pressure in the tube with an eccentric cylindrical insertion |
Acoustic bulletin, Vol. 5 ¹ 2, (2002) |
| The wall pressure fluctuations in a pipe behind a cylindrical insertion with eccentricity are studied. Sharp increase of the pressure in a finite region downstream the insertion, as well as presence of pronounced pressure maximum upstream the point of re-attachment of the separated flow were found. The approximate estimates both for distance from an axisymmetric insertion to the point of maximal pressure and the pressure magnitude at this point were obtained. The study of the wall pressure power spectrum has revealed the low-frequency maxima. Those are the main distinguishing feature of the spectrum under investigation, when comparing to the wall pressure fluctuation spectrum in a fully-developed turbulent pipe flow. These maxima were found to be determined by the appropriate large-scale vortices in regions of separated and re-attached flows, and their frequencies are close to the characteristic frequencies of the vortices formation. The study of the effect of the insertion's eccentricity on the wall pressure statistical characteristics shows that the frequency variation of the eccentricity influences the frequency spectrum stronger then the rms pressure. |
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KEY WORDS: pipe flow, eccentric insertion, wall pressure, pressure spectrum, the frequency of vortex formation |
| TEXT LANGUAGE: Ukrainian |