Method for controlling boundary layer of slender revolving body to keep laminar flow flowing without separation

Abstract

The invention discloses a method for controlling a boundary layer of a slender revolving body to keep laminar flow flowing without separation, relates to the technical field of fluid control, and aimsto increase the forward pressure gradient range as much as possible by optimizing the shape and surface characteristics of the slender revolving body and reduce the change rate of the fluid flowing speed in a reverse pressure gradient area. The laminar flow of the slender revolving body can be kept within a set speed range, flow separation or transition on the surface of the slender revolving body is avoided, the frictional resistance and the differential pressure resistance of the slender revolving body can be greatly reduced, and a good drag reduction effect is achieved; in addition, no extra energy is consumed while resistance reduction is achieved, and the dual effects of saving energy and improving the propelling efficiency are achieved; in addition, the hydrodynamic noise of the slender revolving body without boundary layer separation is also reduced.

Description

technical field [0001] The invention relates to the technical field of fluid control, in particular to a method for controlling the boundary layer of a slender rotating body to maintain laminar flow without separation. Background technique [0002] When the vehicle moves in water, due to the viscosity of water, a boundary layer will be formed near its surface, such as figure 1 As shown, it is the traditional standard shape of the sailing body (a slender body of revolution), that is, a common three-section design, which is composed of an inflow section, a parallel middle body, and an outflow section, and its boundary layer is prone to transition or flow separation, resulting in an increase in the resistance of the vehicle; the resistance of the boundary layer on the vehicle is mainly divided into frictional resistance and pressure resistance, and the resistance is affected by the state of fluid movement: the boundary layer may be in the reverse pressure gradient area on the s...

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Problems solved by technology

[0002] When the vehicle moves in water, due to the viscosity of water, a boundary layer will be formed near its surface, such as figure 1 As shown, it is the traditional standard shape of the sailing body (a slender body of revolution), that is, a common three-section design, which is composed of an inflow section, a parallel middle body, and an outflow section, and its boundary layer is prone to transition or flow separation, resulting in an increase in the resistance of the vehicle; the resistance of the boundary layer on the vehicle is mainly divided into frictional resistance and pressure resistance, and the resistance is affected by the state of fluid movement: the boundary layer may be in the reverse pressure gradient area on the surface of the vehicle When flow separation occurs, the pressure differential resistance will increase significantly; although the turbulent boundary layer is not easy to produce flow separation, it increases the frictional resistance suffered by the vehicle

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