Numerical method for simulating ship propeller wake field

Abstract

The invention relates to a numerical method for simulating a ship propeller wake field. The numerical simulation accuracy of a type of flow fields predominant in vortex motion is improved by forces of two different forms in a momentum equation according to the feature of incompressible flows. The forces of two different forms include a spiral force whose vorticity is in a variable gradient direction and a viscous dissipation force whose vorticity is in the variable gradient direction. The method converts an integral calculation of the spiral force in the calculation grid, of which the vorticity is in the variable gradient direction, into a flux calculation of a force on the boundary of the calculation grid, so that the spatial discretization of the force has a format of higher order accuracy. Meanwhile, the source item of the momentum equation maintains the viscous dissipation force whose vorticity is in the variable gradient direction, so as to improve the convergence and stability of numerical solution. The two forces have different amplification coefficients, so that the accuracy of vorticity can be further maintained, and as a result, the vortex motion of the ship propeller wake field is simulated more accurately.

Description

technical field [0001] The invention relates to a numerical method in the application field of computational fluid dynamics (CFD: Computational Fluid Dynamics), in particular to a numerical method for simulating the wake field of a propeller of a ship. Background technique [0002] Among the various propulsion devices of ships, the propeller has become the most important ship propeller in the world because of its relatively simple structure, high propulsion efficiency, and a long history of development and experimental experience. The propeller is composed of multiple blades, and the rotating blades generate thrust in the water, and its principle is similar to that of an aircraft wing to generate lift. However, the wake flow fields of ship propellers and aircraft wings are quite different. The wake flow field of a ship propeller is called wake field, which is a vortex-dominated incompressible flow field full of vortex flow. figure 1 Taking a blade as an example, the flow p...

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Problems solved by technology

[0009] 2. The spatial discrete precision of the added vorticity is limited and cannot be further improved;

[0010] 3. The stability effect of the source term on the convergence of the numerical solution of the momentum equation is uncertain

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