A Parameterized Control Method of Train Head Shape Based on Fourth-Order Partial Differential Equation

Abstract

The invention discloses a parameterized control method of a locomotive shape based on a fourth-order partial differential equation, which comprises the following steps: step 1: using a fourth-order partial differential equation to parameterize the surface patch of the locomotive shape; step 2: calculating and obtaining a solution The boundary conditions required by the partial differential equation; step 3: get the spatial position of the grid point corresponding to the numerical solution of the partial differential equation; step 4: judge the error between the grid point corresponding to the numerical solution of the partial differential equation in step 3 and the target point Whether it is less than the set threshold; Step 5: Obtain the grid point position corresponding to the solution of the partial differential equation and the corresponding parameters of the local deformation of the partial differential equation control surface when it is closest to the target point; Step 6: Adjust the shape control parameters of the train head , to obtain a new train head model; the invention can not only control the large-scale deformation of the train head model by using a small number of parameters, but also realize the local small-scale shape adjustment, providing more freedom for the train head shape design and aerodynamic optimization Spend.

Description

technical field [0001] The invention relates to the field of high-speed train models, in particular to a parameterized control method for a train head shape based on a fourth-order partial differential equation. Background technique [0002] As the speed of high-speed trains continues to increase, some engineering problems that are ignored at low speeds, such as air resistance, pressure changes in the train, and crosswind effects, consume a lot of energy and limit the further increase of train speeds; existing The study pointed out that for a high-speed train running at a speed of 300km / h, when the length of the head is greater than 5m, the aerodynamic resistance suffered by the train accounts for 85% of the total resistance; The proportion of total drag will be reduced to 75%; thus the locomotive shape design plays a key role in solving these dynamic problems. [0003] The parametric control methods of high-speed trains are mainly divided into three types: parametric model...

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Problems solved by technology

[0003] The parametric control methods of high-speed trains are mainly divided into three types: parametric modeling based on two-dimensional longitudinal contour shape, parametric modeling based on three-dimensional space train head contour, and parametric modeling based on mesh deformation technology; In terms of two-dimensional train longitudinal contour modeling, there are two ways to control the train to control the streamlined longitudinal line of the train, the two-parameter control method and the Hick-Henne equation control method; although the parametric modeling of the two-dimensional train model is optimized for speed It is faster, but it can only control the shape of the longitudinal profile, but cannot control the shape of the deflector, the cab, etc.; in terms of parametric control of the train's front profile in three-dimensional space, the vehicle modeling equation (VMF) method and B- The method of combining spline curve and Coon surface is used to parametrically control the shape of the key position of the train to achieve the control of the head shape of the train; although this method can control the shape of the line at the key position of the train in three-dimensional space, However, it is impossible to adjust the local details of the lofted surface inside the molded line; the grid deformation technology has the ASD method, which mainly controls the shape of the train by changing the position of the grid points of the train calculation grid; this type of method can control the shape of the train Part deformation, but when the calculation mesh of the train is divided into large, changing the shape of the train head will consume a lot of time and storage space

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