O.D.Nikishova Three-dimensional stability of flow over curved moving surface |
Applied hydromechanics, Vol. 2 (74) ¹ 2, (2000) |
| Stability of flow in a boundary layer in respect to three-dimensional longitudinal vortices (Goertler vortices), that are formed under centrifugal effect, is considered. It is shown that the vortices arise over convex surface that moves along curved trajectory in distinction from the case when stationary curved surface is flowed and the vortices are formed over concave surface. The linear stability of the flow is studied and the stability diagram is constructed. It is found that the critical Goertler number is much more than similar critical number for the case when the stationary concave surface is flowed. It is concluded that the flow over curved surface moving along curved trajectory is more stable in comparison with the flow over stationary curved surface. The comprehensive calculations of the eigen functions for different Goertler numbers Gr and non-dimensional wave number aq, where q the impulse thickness are carried out. The graphs of the functions are plotted, the positions and the values of the characteristic points of each function (maximum and minimum values, the crossing of the vertical axes) are found. These data permit to determine all components of the disturbed velocity and the pressure approximately if the information about one component, for example, the maximum value of the longitudinal component of the disturbed velocity that can be measured in experiments is known. The location of the unstability region in respect to three-dimensional longitudinal vortices on the linearly moving dolphin's body, whose afterbody moves up and down, is discussed. |
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KEY WORDS: *** |
| TEXT LANGUAGE: Russian |