To the question of a logarithmic velocity profile correspondence with the experimental data

• Autorzy: Zaryankin A. E.
• Języki publikacji: EN

Abstrakty

EN

The methodology of obtaining a logarithmic velocity profile describing the velocity distribution in the cross section of the boundary layer, which is based on the well-known equation of L. Prandtl, based on its semi-empirical turbulence theory, is considered. It is shown that the logarithmic velocity profile obtained in this way does not satisfy any boundary condition arising from the classical definition of such concept as the boundary layer. The perfect coincidence of this velocity profile with the experimental data of Nikuradze demonstrated in the world scientific literature is a consequence of making these profiles not in a fixed, but in a floating coordinate system. When rebuilding the velocity profiles obtained at different Reynolds numbers, all the profiles lose their versatility and do not coincide with the actual velocity profiles in cylindrical pipes.

Słowa kluczowe

EN

velocity profile; transverse gradient of friction stress; turbulence; boundary layer; coordinate system; boundary conditions; universal velocity profile

PL

profil prędkości; turbulencja; warstwa graniczna; układ współrzędnych; warunki brzegowe; uniwersalny profil prędkości

• Wydawca: Wydawnictwo Politechniki Łódzkiej
• Czasopismo: Mechanics and Mechanical Engineering
• Rocznik: 2018
• Tom: Vol. 22, nr 2
• Strony: 637--647
• Opis fizyczny: Bibliogr. 4 poz., wykr.

Twórcy

autor

Zaryankin A. E.

• National Research University, "Moscow Power Engineering Institute", Moscow, Russian Federation

Bibliografia

• [1] Sedov, L. I.: Continuum mechanics, Science, 2, 1976.
• [2] Loitsyansky, L.G.: Fluid and gas mechanics, Science, 1970.
• [3] Schlichting, H.: Theory of boundary layer, Science, 1969.
• [4] Prandtl, L.: Fluid mechanics, Second ed. RHD, Moscow-Izhevsk, 2002.

Uwagi

Opracowanie rekordu w ramach umowy 509/P-DUN/2018 ze środków MNiSW przeznaczonych na działalność upowszechniającą naukę (2018).