V.A.Voskoboinick, V.T.Grinchenko, A.P.Makarenkov Hydrodynamic noise reduction by high-molecular polymer solutions |
Acoustic bulletin, Vol. 10 ¹ 2, (2007) |
| The paper deals with estimating experimentally the effect of high-molecular polymer supply to turbulent boundary layer of the body of revolution on its hydrodynamic drag and noise. The study was carried out for a turbulent flow over a hydraulically smooth slender body, in which fore part the solutions of linearly chained polymers (of the polyoxiethylene type) were fed through the ring slot. The effect of the input angle for polymeric solution, flow-around velocity, molecular mass and discharge intensity of the polymer on the body hydrodynamic characteristics are investigated. The optimum conditions have been found for slot feeding of the high-molecular polymer providing the maximal hydrodynamic drag and flow noise reduction. The effect of high-molecular polymers on distribution of noise spectral levels has been studied along the flowed surface, as well as with respect to thickness of the turbulent boundary layer. For the system under consideration, the mechanism of polymer influence on the turbulent boundary layer structure and noise sources has been substantiated. |
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KEY WORDS: a turbulent boundary layer, coherent vortex structures, high-molecular polymer solutions, noise spectral levels |
| TEXT LANGUAGE: Russian |