A method for controlling the boundary layer of slender rotors to keep laminar flow without separation

Abstract

The invention discloses a method for controlling the boundary layer of an elongated rotating body to keep laminar flow without separation and flow, and relates to the technical field of fluid control. In addition, reducing the rate of change of the fluid flow velocity in the reverse pressure gradient area is beneficial to keep the laminar flow of the slender rotor within the set velocity range and avoid flow separation or transition on the surface of the slender rotor, which can be greatly reduced. The friction resistance and differential pressure resistance of the slender revolving body have a good drag reduction effect; moreover, the drag reduction is achieved without consuming additional energy, achieving the dual effects of energy saving and improving propulsion efficiency; in addition, no boundary occurs The hydrodynamic noise of the layer-separated elongated rotor 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 an elongated rotating body to keep laminar flow without separation and flow. Background technique [0002] When a vehicle moves in water, a boundary layer will be formed near its surface due to the viscosity of water, such as figure 1 As shown in the figure, it is the traditional standard shape of the sailing body (which is a slender and revolving body), that is, a common three-segment design, which consists of an inflow section, a parallel mid-body and a de-flow section, and its boundary layer is prone to transition or flow. separation, resulting in an increase in the resistance of the sailing body; the resistance acting on the sailing body by the boundary layer is mainly divided into frictional resistance and pressure difference resistance, and the magnitude of the resistance is affected by the fluid motion state: the boundar...

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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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