Speed profile generation method based on relative coordinates

Abstract

The invention aims to provide a speed profile generation method based on relative coordinates, and belongs to the field of fluid analysis. Comprising the following steps: inputting a physical field and geometric conditions; selecting a monitoring interval; generating curve equidistant points in the interval based on the monitoring interval; generating corresponding tangent lines and angles based on the equidistant points; according to the obtained tangent line and the corresponding angle, speed conversion of the corresponding monitoring point is completed in combination with an existing physical field, and the speed conversion comprises the tangential speed and the normal speed. According to the method, curve equidistant points can be divided in the monitoring interval, the angle of the corresponding position is obtained to correct the relative speed, and a plurality of corresponding speed molded lines are generated according to the curve equidistant points, so that the relative speed molded lines are compared under the condition that uniform curve intervals are ensured, and the effectiveness and rationality of speed molded line comparison are ensured.

Description

Technical Field

[0001] The present invention relates to a fluid analysis method, specifically a method for generating velocity profiles. Background Technology

[0002] Current velocity profile analysis methods suffer from several fundamental flaws that urgently need to be addressed. Traditional methods simply use velocity components in an absolute coordinate system to select the velocity source, completely ignoring the essential characteristics of curved surface flow. When fluid flows over a curved wall, its true direction of motion should follow the wall tangent, not an artificially defined absolute coordinate direction. Directly using absolute velocity components as the analysis object leads to the incorrect decomposition of tangential velocity and the mixing of normal velocity with the tangential projection, resulting in significant deviations in both velocity amplitude and direction, severely impacting the accurate assessment of flow characteristics.

[0003] Regarding the distribution of velocity profile sampling points, existing technologies mechanically employ a vertical distribution strategy under an absolute coordinate system. This rigid approach severely conflicts with the geometric characteristics of curved surfaces. When the wall has curvature, vertical sampling using absolute coordinates results in uneven actual flow distances between adjacent sampling points, with the normal direction deviating from the true wall normal. This not only leads to inaccurate boundary layer parameter measurements but also renders velocity profile data from different curvature regions incomparable, severely limiting comparative analysis of curved surface flows.

[0004] Current velocity profile spacing standards suffer from serious applicability issues. Using absolute coordinates for equidistant sampling in the x-direction completely deviates from the physical nature of fluid motion. In regions of curvature variation, the same x-interval corresponds to significantly different flow path lengths, which not only distorts the velocity gradient distribution but also introduces spurious geometric distortions into turbulence characteristic analysis. This absolute coordinate-based spacing standard causes a systematic deviation between the acquired flow information and real physical phenomena, severely limiting the accurate prediction capability of complex curved surface flows. Summary of the Invention

[0005] The purpose of this invention is to provide a velocity profile generation method based on relative coordinates that can compare relative velocity profiles while ensuring uniform curve intervals, thereby ensuring the effectiveness and rationality of velocity profile comparison.

[0006] The objective of this invention is achieved as follows: This invention discloses a method for generating velocity profiles based on relative coordinates, characterized by comprising the following steps: (1) Input the actual physical field and geometric conditions of the calculation model; (2) Select monitoring range based on actual needs: Construct the monitoring range according to monitoring needs and actual characteristic locations; (3) Based on the selected monitoring interval, select the equidistant points of the curve as the relative longitudinal lowest reference points of the velocity profile: In the selected monitoring interval, arrange the equidistant points of the curve with a uniform curve distance at intervals according to the accuracy requirements as the longitudinal lowest reference points of the velocity profile. (4) Based on the selected curve equidistant points, generate the tangent, angle and velocity profile monitoring points at the corresponding positions: Based on the selected curve equidistant monitoring points, generate the tangent at the corresponding positions, thereby obtaining the angle at the position of each reference, thereby generating the relative longitudinal monitoring points of the velocity profile with each reference point as the lowest reference, thereby forming the data detection line of each velocity profile, and thereby obtaining the data. (5) Based on the data obtained in step (4), the velocities in the absolute coordinates of the original physical field, including the flow velocity in the absolute direction and the vertical flow velocity in the absolute direction, are converted into relative velocities in the tangential and normal directions relative to the monitoring point. (6) Generate velocity profiles of relative velocities at different positions; (7) Output velocity profile diagrams based on relative coordinates at different positions.

[0007] The present invention may also include: 1. In step (1), a high-precision physical field corresponding to coordinate-physical property parameters is obtained through CFD fluid simulation technology; at the same time, a geometric model matching the CFD calculation is input.

[0008] 2. The specific content of step (3) is: N1, N2, N3...N n There are n reference points in total, among which... in The length of the monitoring range curve already calibrated on the surface of the geometric model. The density of monitoring points is selected based on requirements and characteristic locations. This represents the number of monitoring points within the monitoring interval.

[0009] 3. The specific content of step (4) includes: generating n tangent lines at the corresponding positions based on the n equidistant monitoring points (i.e., reference points) on the selected curve, thereby obtaining the angle of each reference point. , , ... This generates n columns of relative longitudinal monitoring points for velocity profiles, with each reference point serving as the lowest reference, based on the angle of each reference point. This results in n data detection lines for each velocity profile, where the direction of each detection line is determined by the angle of the reference point measured above. The determination is that each detection line is perpendicular to the geometric wall at that location, thereby acquiring all the data.

[0010] 4. In step (5), the absolute flow velocity and the absolute vertical flow velocity are determined based on the angle measured in step (4). This is converted into relative velocities in the tangential and normal directions relative to the monitoring point, where: in , This represents the flow direction and velocity perpendicular to the flow in the original grid data, i.e., in absolute coordinates. , These represent the tangential and normal velocities at the corresponding positions after coordinate transformation. The local angle of the reference point measured in step (4).

[0011] 5. Step (6) is as follows: using uniform curve distance as the variable to distinguish different velocity profiles, that is, using the change of curve distance as a reference to analyze the change of velocity profile, thereby generating a uniform curve interval that is different from the classic velocity profile with a single direction interval, showing the relative velocity profile of the fluid boundary layer near the wall.

[0012] The advantages of this invention are: 1. This invention optimizes the rationality of velocity profile comparison by selecting reasonable equidistant points on the curve within the monitoring interval, thereby ensuring the accuracy of the data source points in terms of coordinates and location. 2. This invention determines the tangents and angles at equidistant points on the curve, thereby converting the velocities in the original physical field under absolute coordinates, such as flow velocity and vertical flow velocity, into relative tangential and normal velocities relative to the monitoring points, ensuring the correctness of data selection and applicability at the physical level. Attached Figure Description

[0013] Figure 1 This is a flowchart of the present invention; Figure 2 This is a schematic diagram illustrating the working principle of the present invention; Figure 3 This is a schematic diagram of the velocity profile after the transformation. Detailed Implementation

[0014] The invention will now be described in more detail with reference to the accompanying drawings: Combination Figure 1-3 The present invention provides a method for generating velocity profiles based on relative coordinates, comprising the following steps: (1) Input the actual physical field and geometric conditions of the calculation model; (2) Select monitoring range based on actual needs: Construct the monitoring range according to monitoring needs and actual characteristic locations; (3) Based on the selected monitoring interval, select the equidistant points of the curve as the relative longitudinal lowest reference points of the velocity profile: In the selected monitoring interval, arrange the equidistant points of the curve with a uniform curve distance at intervals according to the accuracy requirements as the longitudinal lowest reference points of the velocity profile. (4) Based on the selected curve equidistant points, generate the tangent, angle and velocity profile monitoring points at the corresponding positions: Based on the selected curve equidistant monitoring points, generate the tangent at the corresponding positions, thereby obtaining the angle at the position of each reference, thereby generating the relative longitudinal monitoring points of the velocity profile with each reference point as the lowest reference, thereby forming the data detection line of each velocity profile, and thereby obtaining the data. (5) Based on the data obtained in step (4), the velocities in the absolute coordinates of the original physical field, including the flow velocity in the absolute direction and the vertical flow velocity in the absolute direction, are converted into relative velocities in the tangential and normal directions relative to the monitoring point. (6) Generate velocity profiles of relative velocities at different positions; (7) Output velocity profile diagrams based on relative coordinates at different positions; In step (1), a high-precision physical field with a one-to-one correspondence between coordinates and physical property parameters is obtained through traditional CFD fluid simulation technology; at the same time, a geometric model that matches the CFD calculation is input.

[0015] In step (3), based on the monitoring requirements and actual characteristic locations in step (2), equidistant points on the curve are selected as the relative longitudinal lowest reference points of the velocity profile: within the selected monitoring interval, equidistant points on the curve with uniform curve distances are arranged according to the accuracy requirements as the longitudinal lowest reference points of the velocity profile, namely N1, N2, N3...N n There are n reference points in total, among which... in The length of the monitoring range curve already calibrated on the surface of the geometric model. The density of monitoring points is selected based on requirements and characteristic locations. This represents the number of monitoring points within the monitoring interval.

[0016] In step (4), based on the selected equidistant points on the curve, the tangents, angles, and velocity profiles at the corresponding positions are generated. For the remaining monitoring points: based on the n equidistant monitoring points, i.e., the reference points, on the selected curve, n tangents at the corresponding positions are generated, thereby obtaining the angles at the positions of each reference point. , , ... This generates n columns of relative longitudinal monitoring points for velocity profiles, with each reference point serving as the lowest reference, based on the angle of each reference point. This results in n data detection lines for each velocity profile, where the direction of each detection line is determined by the angle of the reference point measured above. The determination is that each detection line is perpendicular to the geometric wall at that location, thereby acquiring all the data.

[0017] In step (5), the absolute flow velocity and the absolute vertical flow velocity are determined based on the angle measured in step (4). This is converted into relative velocities in the tangential and normal directions relative to the monitoring point, where: Among them , This represents the flow direction and velocity perpendicular to the flow in the original grid data, i.e., in absolute coordinates. , These represent the tangential and normal velocities at the corresponding positions after coordinate transformation. The local angle of the reference point measured in step (4); After summarizing the data in step (5), the uniform curve distance is used as the variable to distinguish different velocity profiles. That is, the change of the curve distance is used as a reference to analyze the change of the velocity profile, thereby generating a uniform curve interval that is different from the classic velocity profile with a single direction interval, showing the relative velocity profile of the fluid boundary layer near the wall.

[0018] The overall process is as follows: First, input the actual physical field and geometric conditions of the calculation model. Based on actual needs, determine the geometric interval required for calculation, including the start and end points of the curved surface of the interval, the normal height of the interval, the number and density of points selected for flow and normal directions within the interval, etc. Based on the selected monitoring interval, select equidistant points of the curve. Set parameters according to the obtained monitoring interval conditions to generate several velocity monitoring points within the interval. Based on the selected equidistant points of the curve, generate the tangent and angle at the corresponding positions. Based on the first layer of monitoring points on the generated curved surface, generate the tangent at the corresponding positions and obtain its tangent angle according to the tangent function. Then, generate the corresponding sine and cosine values ​​according to the angle at the corresponding position and correct the coordinates of the monitoring points from the second layer to the highest point of the normal direction of each velocity profile. Based on the data obtained in the steps, convert the velocities in the absolute coordinates of the original physical field, such as flow velocity and perpendicular flow velocity, into relative velocities relative to the tangent and normal directions of the monitoring points. Based on the obtained data, transform the velocities in the absolute coordinates of the original physical field according to the angle at the corresponding position using sine and cosine functions. Finally, complete the generation of velocity profiles based on relative coordinates.

Claims

1. A method for generating velocity profiles based on relative coordinates, characterized in that: Includes the following steps: (1) Input the actual physical field and geometric conditions of the calculation model; (2) Select monitoring range based on actual needs: Construct the monitoring range according to monitoring needs and actual characteristic locations; (3) Based on the selected monitoring interval, select the equidistant points of the curve as the relative longitudinal lowest reference points of the velocity profile: In the selected monitoring interval, arrange the equidistant points of the curve with a uniform curve distance at intervals according to the accuracy requirements as the longitudinal lowest reference points of the velocity profile. (4) Based on the selected curve equidistant points, generate the tangent, angle and velocity profile monitoring points at the corresponding positions: Based on the selected curve equidistant monitoring points, generate the tangent at the corresponding positions, thereby obtaining the angle at the position of each reference, thereby generating the relative longitudinal monitoring points of the velocity profile with each reference point as the lowest reference, thereby forming the data detection line of each velocity profile, and thereby obtaining the data. (5) Based on the data obtained in step (4), the velocities in the absolute coordinates of the original physical field, including the flow velocity in the absolute direction and the vertical flow velocity in the absolute direction, are converted into relative velocities in the tangential and normal directions relative to the monitoring point. (6) Generate velocity profiles of relative velocities at different positions; (7) Output velocity profile diagrams based on relative coordinates at different positions.

2. The velocity profile generation method based on relative coordinates according to claim 1, characterized in that: In step (1), a high-precision physical field corresponding to coordinates and physical property parameters is obtained through CFD fluid simulation technology; at the same time, a geometric model matching the CFD calculation is input.

3. The velocity profile generation method based on relative coordinates according to claim 1, characterized in that: Step (3) consists of: N1, N2, N3...N n There are n reference points in total, among which... in The length of the monitoring range curve already calibrated on the surface of the geometric model. The density of monitoring points is selected based on requirements and characteristic locations. This represents the number of monitoring points within the monitoring interval.

4. The velocity profile generation method based on relative coordinates according to claim 1, characterized in that: Step (4) specifically includes: generating n tangent lines at the corresponding positions based on the n equidistant monitoring points (i.e., reference points) on the selected curve, thereby obtaining the angle of each reference point. , , ... This generates n columns of relative longitudinal monitoring points for velocity profiles, with each reference point serving as the lowest reference, based on the angle of each reference point. This results in n data detection lines for each velocity profile, where the direction of each detection line is determined by the angle of the reference point measured above. The determination is that each detection line is perpendicular to the geometric wall at that location, thereby acquiring all the data.

5. The velocity profile generation method based on relative coordinates according to claim 1, characterized in that: In step (5), the absolute flow velocity and the absolute vertical flow velocity are determined based on the angle measured in step (4). This is converted into relative velocities in the tangential and normal directions relative to the monitoring point, where: in , This represents the flow direction and velocity perpendicular to the flow in the original grid data, i.e., in absolute coordinates. , These represent the tangential and normal velocities at the corresponding positions after coordinate transformation. The local angle of the reference point measured in step (4).

6. The velocity profile generation method based on relative coordinates according to claim 1, characterized in that: Step (6) specifically involves using uniform curve distance as the variable to distinguish different velocity profiles, that is, using the change of curve distance as a reference to analyze the change of velocity profile, thereby generating a uniformly spaced velocity profile that is different from the classic velocity profile that is spaced in a single direction, and showing the relative velocity profile of the fluid boundary layer near the wall.

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