Method and system for studying influence of inner wall roughness on flow-induced vibration characteristics of flow conveying pipeline

Abstract

The invention discloses a method and a system for studying the influence of inner wall roughness on flow-induced vibration characteristics of a flow conveying pipeline, belongs to the technical field of coupling dynamics, and solves the problem that a transverse motion differential equation of the pipeline under the influence of variable roughness is difficult to accurately express. The method comprises the steps that S1, a transverse motion equation of the variable-roughness fluid conveying pipeline is established; s2, according to the transverse motion equation, a Galerkin method is adopted to carry out finite term superposition, and a characteristic solution of the fluid conveying pipeline is obtained; and S3, according to the characteristic solution of the fluid conveying pipeline, combining with any given working condition to realize the flow-induced vibration characteristic detection of the fluid conveying pipeline. The method is suitable for application scenarios such as fluid conveying pipeline system design optimization.

Description

Technical Field

[0001] The present invention belongs to the technical field of coupling dynamics, and particularly relates to a technology for analyzing the flow-induced vibration characteristics of a pipeline with variable roughness for conveying fluid. Background Technique

[0002] With the rapid development of science and technology, the research on fluid-structure interaction dynamics by scholars has been continuously enriched, and pipelines for conveying fluid are used in more and more extensive scenarios, such as: rocket launcher propulsion systems, nuclear reactor cooling systems, automotive fuel supply systems, urban water supply systems, farmland irrigation systems, etc. In view of this, the research on the fluid-structure interaction dynamics behavior of pipelines has also attracted the interest of many scholars and a large number of research results have been published. The fluid-structure interaction dynamics behavior of pipelines for conveying fluid has become a typical mechanical problem, and the research on it can radiate to the perfect solution of applied mechanical problems in other fields.

[0003] Regarding the fluid-structure interaction dynamics problem of pipelines for conveying fluid, according to the classification of research means, it can be roughly divided into two research branches, namely: experimental research and theoretical research. In terms of theoretical research, the basic research route can be summarized as follows: (1) Transform the actual problem into a structural dynamics problem through abstraction, approximation, etc.; (2) Select appropriate modeling theories and tools to represent the above mechanical problem as a motion equation in which the displacement varies with time and space; (3) Discretize the above motion equation using existing or improved or newly proposed numerical algorithms, and solve it in combination with boundary conditions and initial conditions. In recent years, based on the above three basic steps, scholars have studied many fluid-structure interaction dynamics problems of pipelines, mainly including two aspects: flow-induced vibration and forced vibration. Flow-induced vibration also includes problems such as stability and chaotic motion. Among them, the stability problem is the research focus of many scholars. With the development of science and technology and research means, regarding the fluid-structure interaction dynamics problem of pipelines for conveying fluid, the research content is gradually developing towards complexity, refinement, and non-linearity, which puts forward higher requirements for future research.

[0004] After processing, the inner wall roughness of the pipeline naturally exists, and due to the limitations of processing technical means, there are obvious differences in the roughness of the pipeline ends and the middle section. Therefore, it is very difficult to study the lateral motion law of the pipeline on the premise that the inner wall roughness is not a constant value. The core difficulty lies in how to accurately establish the lateral motion differential equation of the pipeline under the influence of variable roughness. Summary of the Invention

[0005] The present invention proposes a method and system for studying the influence of inner wall roughness on the flow-induced vibration characteristics of a pipeline for conveying fluid, and its purpose is to solve the problem that it is difficult to accurately express the lateral motion differential equation of the pipeline under the influence of variable roughness.

[0006] The present invention proposes a method for studying the influence of inner wall roughness on flow-induced vibration characteristics of a fluid delivery pipeline, comprising:

[0007] S1: Establish the lateral motion equation of the fluid conveying pipeline with variable roughness;

[0008] S2: Based on the lateral motion equation, the Galerkin method is used to perform finite term superposition to obtain the characteristic solution of the fluid conveying pipeline;

[0009] S3: Based on the characteristic solution of the fluid pipeline and any given working conditions, the flow-induced vibration characteristics of the fluid pipeline are detected.

[0010] Furthermore, a preferred solution is provided: S1 includes:

[0011] S1.1: Determine the effect of variable roughness on the lateral motion equations of a fluid conveying pipeline;

[0012] S1.2: Based on the effect of variable roughness on the lateral motion equation of the fluid conveying pipeline, derive the lateral motion equation of the fluid conveying pipeline with variable roughness;

[0013] S1.3: Perform dimensionless treatment of the lateral motion equations and boundary conditions.

[0014] Furthermore, a preferred solution is provided: the S1.1 includes: based on the difference in roughness between the end portion and the middle portion of the pipeline, a piecewise function is used to express the roughness of the pipeline, and the function is introduced into the expression of the centrifugal force of the fluid.

[0015] Furthermore, a preferred solution is provided: S1.2 includes: on the premise that the lateral movement of the fluid delivery pipeline conforms to the Euler-Bernoulli beam model, the lateral motion equation of the fluid delivery pipeline is established according to Newton's second law of motion, and the equation includes the bending restoring force of the pipeline, the revised centrifugal force of the fluid, the Coriolis force of the fluid, and the inertial force of the fluid and the pipeline.

[0016] Furthermore, a preferred solution is provided: S2 includes:

[0017] S2.1: Construct shape functions;

[0018] S2.2: Derived flow-induced vibration characteristic solution based on the shape function.

[0019] Furthermore, a preferred solution is provided: S2.1 includes: separating the solution of the lateral motion equation in time and space, and deriving the spatial solution by using the differential transformation method. At the same time, the boundary conditions are also processed by the differential transformation method. Finally, the characteristic equation of the pipeline with zero velocity under a given support form is obtained by simultaneous equations. The characteristic solution is obtained by numerically solving the characteristic equation, and the characteristic solution is substituted into the solution of the motion equation to obtain the modal function corresponding to the characteristic solution. This series of modal functions is taken as the shape function in the Galerkin method.

[0020] Furthermore, a preferred solution is provided: S2.2 includes: using the Galerkin method to separate the variables of the equation by using the modal function, and constructing the stiffness matrix, mass matrix and damping matrix of the system through simplification, and then deriving the characteristic equation of the system and the expression for solving the characteristic solution.

[0021] The present invention also proposes a computer device, which includes a memory and a processor. A computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes a method for studying the influence of inner wall roughness on the flow-induced vibration characteristics of a fluid conveying pipeline according to any one or more of the above-mentioned schemes in combination.

[0022] The present invention also proposes a computer-readable storage medium for storing a computer program, and the computer program executes a method for studying the influence of inner wall roughness on the flow-induced vibration characteristics of a fluid conveying pipeline according to any one or more of the above-mentioned schemes in combination.

[0023] The present invention also proposes a system for studying the influence of inner wall roughness on the flow-induced vibration characteristics of a fluid conveying pipeline. The system is implemented based on a method for studying the influence of inner wall roughness on the flow-induced vibration characteristics of a fluid conveying pipeline according to any one or more of the above-mentioned schemes in combination. The system includes:

[0024] Equation establishment module: used to establish the lateral motion equation of a fluid conveying pipeline with variable roughness;

[0025] Characteristic detection module: used to perform finite-term superposition by using the Galerkin method according to the lateral motion equation to obtain the characteristic solution of the fluid conveying pipeline; according to the characteristic solution of the fluid conveying pipeline and in combination with any given working condition, realize the detection of the flow-induced vibration characteristics of the fluid conveying pipeline.

[0026] Compared with the prior art, the advantages of the present invention are:

[0027] The method proposed by the present invention takes into account the influence of inner wall roughness in the traditional differential equation of the transverse motion of the fluid-carrying pipeline, and considers the difference in roughness between the pipeline ends and the middle section. The roughness distribution along the entire pipeline is expressed in the form of a piecewise function, and then it is introduced into the expression of the fluid centrifugal force. On this basis, the transverse motion equation of the fluid-carrying pipeline system is established.

[0028] The method proposed by the present invention describes the variable roughness with a piecewise function and introduces it into the mathematical expression of the fluid centrifugal force. By adjusting the upper and lower limits of the piecewise interval, the influence of the inner wall roughness on the flow-induced vibration characteristics of the fluid-carrying pipeline can be studied, which has reference significance for the study of the fluid-structure interaction dynamics problems of other fluid-carrying pipelines with piecewise attributes (such as inner and outer diameters, etc.).

[0029] When using the Galerkin method to discretize and solve the motion equation in the method described by the present invention, the modal function derived by the differential transformation method is used as the shape function, which is also applicable to the study of similar problems of bent pipes and has reference value for the study of fluid-structure interaction problems in other fields.

[0030] The method idea described by the present invention is concise, the algorithm scale is small and it is convenient for transplantation and modification, and it is easy to be implemented in engineering.

[0031] The present invention is applicable to application scenarios such as the design optimization of fluid-carrying pipeline systems. Description of the Drawings

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0033] Figure 1 It is a flowchart of a method for studying the influence of inner wall roughness on the flow-induced vibration characteristics of a fluid-carrying pipeline according to the first specific embodiment of the present invention;

[0034] Figure 2 It is a mechanical model diagram of the fluid-carrying pipeline according to the second specific embodiment of the present invention. Specific Embodiments

[0035] In the following description, for the purpose of illustration rather than limitation, specific details such as specific system structures and technologies are proposed to thoroughly understand the embodiments of the present application. However, those skilled in the art should clearly understand that the present application can also be implemented in other embodiments without these specific details. In other cases, the detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from obstructing the description of the present application.

[0036] It will be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0037] It should also be understood that the terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0038] The following is a clear and complete description of the technical solutions in the embodiments of this application in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0039] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific implementation methods disclosed below.

[0040] Implementation method one:

[0041] Reference Figure 1 This embodiment will be described.

[0042] This embodiment provides a method for studying the effect of inner wall roughness on flow-induced vibration characteristics of a fluid delivery pipeline, the method comprising:

[0043] S1: Establish the lateral motion equation of the fluid conveying pipeline with variable roughness;

[0044] S2: Based on the lateral motion equation, the Galerkin method is used to perform finite term superposition to obtain the characteristic solution of the fluid conveying pipeline;

[0045] S3: Based on the characteristic solution of the fluid pipeline and any given working conditions, the flow-induced vibration characteristics of the fluid pipeline are detected.

[0046] Specifically:

[0047] Said S1 comprises:

[0048] S1.1: Effect of variable roughness on the lateral motion equations of fluid conveying pipelines:

[0049] Traditional differential equations for the lateral motion of fluid pipelines include the pipeline's bending restoring force, the fluid's centrifugal force, the fluid's Coriolis force, and the inertial forces of the fluid and pipeline. Inner wall roughness directly affects the fluid's flow pattern, and therefore, the centrifugal force expression. Therefore, a correction to the centrifugal force term in the final equation of motion can express the effect of roughness on the pipeline's lateral motion equations. Furthermore, considering the difference in roughness between the ends and the middle of the pipeline, the uneven distribution of roughness along the entire pipeline is expressed using a piecewise function and incorporated into the expression for the fluid's centrifugal force.

[0050] S1.2: Derivation of the equations of lateral motion for fluid conveying pipelines considering variable roughness:

[0051] On the premise that the lateral movement of the pipeline conforms to the Euler-Bernoulli beam model, the lateral motion equation of the pipeline system is established according to Newton's second law of motion. The equation includes four parts: the bending restoring force of the pipeline, the revised centrifugal force of the fluid, the Coriolis force of the fluid, and the inertial force of the fluid and the pipeline.

[0052] S1.3: Dimensionless Treatment of Equations of Motion and Boundary Conditions:

[0053] The motion equations and boundary conditions are treated dimensionlessly. In this way, in subsequent calculations and analytical discussions, dimensionless parameters are used to replace the original parameters, which is simple and clear in writing and understanding.

[0054] The S2 includes:

[0055] S2.1: Construction of shape functions:

[0056] Based on the idea of separation of variables method, the solution of the motion equation is separated in time and space, and the spatial solution is derived by differential transformation. At the same time, the boundary conditions are processed in the same way. Finally, the characteristic equation of the pipeline when the velocity is zero under a given support form is obtained by joint equations. The characteristic solution can be obtained by numerically solving the characteristic equation. The characteristic solution is substituted back into the solution of the motion equation to obtain the modal function corresponding to the characteristic solution. This series of modal functions is taken as the shape function in the Galerkin method.

[0057] S2.2: Derivation of characteristic solutions for flow-induced vibrations:

[0058] The lateral motion equations of the piping system are homogeneous. Using the Galerkin method, we first separate the variables of this homogeneous differential equation using the modal functions in S2.1. Then, through simplification, we construct the system's stiffness, mass, and damping matrices. This allows us to derive the system's characteristic equation and the expression for the characteristic solution. The characteristic solution obtained here is a complex number, the real part of which is the natural frequency of the pipeline when it vibrates.

[0059] This embodiment discloses the transverse motion differential equation of a fluid-conveying pipeline considering the inner wall roughness, and subsequently derives the fluid-induced vibration characteristics of the fluid-conveying pipeline. This embodiment simplifies the calculation of the inner wall roughness, and the idea of solving the problem is simple, with good universality, and is easy to be extended to the research of similar problems of fluid-conveying elbows or other connection forms.

[0060] Embodiment 2:

[0061] Refer to Figure 2 to illustrate this embodiment.

[0062] This embodiment further illustrates a method for studying the influence of inner wall roughness on the fluid-induced vibration characteristics of a fluid-conveying pipeline described in Embodiment 1.

[0063] This embodiment includes the following steps:

[0064] The first step: Establish the transverse motion equation of a fluid-conveying pipeline considering variable roughness:

[0065] There are three sub-steps for establishing the transverse motion equation of a fluid-conveying pipeline considering roughness:

[0066] (1) Influence of variable roughness on the transverse motion equation of a fluid-conveying pipeline:

[0067] If w is the transverse displacement, x and t represent the axial coordinate and time respectively, m f and m p are the masses of the fluid and the pipeline per unit length respectively, ρ f and U represent the density and average flow velocity of the fluid in the cross-section respectively, and the overall mechanical model is as shown in Figure 2 , then the expression of the traditional transverse motion differential equation of the fluid-conveying pipeline is as follows:

[0068]

[0069] On the left side of the equation, from left to right in turn are the bending restoring force of the pipeline, the centrifugal force of the fluid, the Coriolis force of the fluid, and the inertial forces of the fluid and the pipeline. The inner wall roughness directly affects the flow pattern of the fluid, that is, affects the expression of the centrifugal force of the fluid. Generally, a flow model correction factor α is introduced to represent this influence, that is

[0070]

[0071] However, considering the difference in roughness between the pipeline end and the middle section, the distribution of roughness along the entire pipeline is not uniform. Therefore, the present invention uses a piecewise function to express it, that is, the correction factor is adjusted at the place where there is a difference in roughness, which means that if there are several differences in the overall pipeline, there will be the same number of adjustments to the correction factor. Based on this, the motion equation of the overall pipeline can be finally described.

[0072] (2) Derivation of the transverse motion equation of the fluid delivery pipeline:

[0073] If we take the case of one roughness difference (the same applies to multiple differences) as an example, the correction factor corresponding to the left end (assuming the length is L1) is α1, and the correction factor corresponding to the remaining part is α2:

[0074]

[0075] in:

[0076] h={H(x),-H(xL),-H(x-L1)} T ,λ={1,λ,1-λ} (4)

[0077] Where H(x) represents a unit step function, and λ = α2 / α1.

[0078] Figure 2 The boundary conditions of the fluid delivery pipeline shown can be expressed as:

[0079] w(0,t)=w′(0,t)=w″(L,t)=w″′(L,t)=0 (5)

[0080] (3) Dimensionless treatment of motion equations and boundary conditions:

[0081] To facilitate subsequent analysis and discussion, the equations of motion and boundary conditions are dimensionless, and the following dimensionless parameters are introduced:

[0082]

[0083] Therefore, the dimensionless equation of motion can be expressed as:

[0084]

[0085] Where,

[0086] h0={H(ξ),-H(ξ-1),-H(ξ-ξ1)} T

[0087] Similarly, formula (5) can be transformed into:

[0088] η(0,τ)=η′(0,τ)=η″(1,τ)=η″′(1,τ)=0 (8)

[0089] The second step is to use the Galerkin method to derive the characteristic solution of the fluid pipeline:

[0090] Based on the equation of motion obtained in the first step, the Galerkin method is used to perform finite term superposition to derive the characteristic solution of the catheter system. This method includes the following two substeps:

[0091] (1) Construction of shape functions:

[0092] In this embodiment, the modal functions of the Euler - Bernoulli beam are used as the shape functions in the Galerkin method. Based on this idea, the modal functions of the cantilevered fluid - conveying pipeline when the flow velocity is 0 can be derived by the differential transformation method as follows:

[0093]

[0094] where, represents the n - th natural frequency, N0 is the number of iterations in the differential transformation method, i.e., the n - th modal function.

[0095] (2) Derivation of the characteristic solution of fluid - induced vibration:

[0096] According to the principle of the Galerkin method, the solution of Equation (7) can be expressed as:

[0097]

[0098] where, N represents the number of superposition terms, i.e., the n - th shape function, which is also Equation (9), q n (τ) is the n - th generalized coordinate.

[0099] Substituting Equation (10) into Equation (7), we get:

[0100]

[0101] Multiplying each shape function by Equation (11) and integrating the result with respect to ξ in the interval [0,1], the result is:

[0102]

[0103] where,

[0104]

[0105] Equation (12) can be expressed in vector form as:

[0106]

[0107] The solution of Equation (13) can be expressed as:

[0108] q = q0exp(iωτ) (14)

[0109] where, represents the dimensionless eigenvalue, and Ω is the dimensional eigenvalue.

[0110] Substituting (14) into Equation (13), we get:

[0111] [K + iωG - ω 2 M]q0 = 0 (15)

[0112] Since q0 ≠ 0, the determinant of its coefficient matrix must be 0, that is:

[0113] |K + iωG - ω 2 M| = 0 (16)

[0114] By solving Equation (16), the eigenvalues ω j (j = 1, 2, 3, …) of the system can be obtained. The real part (denoted by Re(ω)) is the dimensionless natural frequency, and the imaginary part (denoted by Im(ω)) is related to the damping.

[0115] Embodiment 3:

[0116] This embodiment proposes a system for studying the fluid-induced vibration characteristics of a fluid-conveying pipeline with inner wall roughness. The system is implemented based on a method for studying the fluid-induced vibration characteristics of a fluid-conveying pipeline with inner wall roughness described in any one of Embodiment 1 or Embodiment 2. The system includes:

[0117] Equation establishment module: used to establish the lateral motion equation of a fluid-conveying pipeline with variable roughness;

[0118] Characteristic detection module: used to obtain the characteristic solutions of the fluid-conveying pipeline by using the Galerkin method for finite-term superposition according to the lateral motion equation; and to realize the detection of the fluid-induced vibration characteristics of the fluid-conveying pipeline according to the characteristic solutions of the fluid-conveying pipeline and in combination with any given working conditions.

[0119] Those skilled in the art can understand that the above is only the preferred embodiment of the present invention. The features described in each embodiment and / or claim of the present disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in the present disclosure. It is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0120] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they know the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0121] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

[0122] Those skilled in the art should understand that the embodiments of the present disclosure can be provided as a method, a system, or a computer program product. Therefore, the present disclosure can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present disclosure can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0123] The present disclosure is described with reference to the flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present disclosure. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and combinations of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processors of general-purpose computers, special-purpose computers, embedded processors, or other programmable data processing devices to generate a machine, such that the instructions executed by the processors of the computer or other programmable data processing devices produce means for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks. These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory produce a manufactured article including instruction means that implement the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0124] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure rather than limit the scope of its protection. Although the present disclosure has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that after reading the present disclosure, various changes, modifications or equivalent replacements can still be made to the specific implementation manners of the invention. However, these changes, modifications or equivalent replacements are all within the scope of protection of the claims pending for publication.

Claims

1. A method for studying the effect of inner wall roughness on flow-induced vibration characteristics of a fluid delivery pipeline, characterized in that: The method includes: S1: Establish the lateral motion equation of the fluid - conveying pipeline with variable roughness; S2: According to the lateral motion equation, use the Galerkin method for finite - term superposition to obtain the characteristic solution of the fluid - conveying pipeline; S3: According to the characteristic solution of the fluid - conveying pipeline, combined with any given working conditions, realize the detection of the fluid - induced vibration characteristics of the fluid - conveying pipeline.

2. The method for studying the effect of inner wall roughness on flow-induced vibration characteristics of a fluid delivery pipeline according to claim 1, characterized in that: The S1 includes: S1.1: Determine the influence of variable roughness on the lateral motion equation of the fluid - conveying pipeline; S1.2: According to the influence of variable roughness on the lateral motion equation of the fluid - conveying pipeline, derive the lateral motion equation of the fluid - conveying pipeline with variable roughness; S1.3: Nondimensionalize the lateral motion equation and boundary conditions.

3. The method for studying the effect of inner wall roughness on flow-induced vibration characteristics of a fluid delivery pipeline according to claim 2, characterized in that: The S1.1 includes: According to the difference in roughness between the pipeline end and the middle section, use a piece - wise function to express the roughness of the pipeline and introduce it into the expression of the fluid centrifugal force.

4. The method for studying the effect of inner wall roughness on flow-induced vibration characteristics of a fluid delivery pipeline according to claim 2, characterized in that: The S1.2 includes: On the premise that the lateral motion of the fluid - conveying pipeline conforms to the Euler - Bernoulli beam model, establish the lateral motion equation of the fluid - conveying pipeline according to Newton's second law of motion. The equation includes the bending restoring force of the pipeline, the revised fluid centrifugal force, the fluid Coriolis force, and the inertial forces of the fluid and the pipeline.

5. The method for studying the effect of inner wall roughness on flow-induced vibration characteristics of a fluid delivery pipeline according to claim 1, characterized in that: The S2 includes: S2.1: Construct the shape function; S2.2: Derive the fluid - induced vibration characteristic solution according to the shape function.

6. The method for studying the effect of inner wall roughness on flow-induced vibration characteristics of a fluid delivery pipeline according to claim 5, characterized in that: The S2.1 includes: Separate the time and space of the solution of the lateral motion equation, and use the differential transformation method to derive the spatial solution. At the same time, use the differential transformation method for the boundary conditions. Finally, obtain the characteristic equation of the pipeline when the velocity is zero under a given support form by simultaneous solution. Obtain the characteristic solution by numerically solving the characteristic equation, substitute the characteristic solution into the solution of the motion equation to get the modal function corresponding to the characteristic solution, and take this series of modal functions as the shape function in the Galerkin method.

7. The method for studying the effect of inner wall roughness on flow-induced vibration characteristics of a fluid delivery pipeline according to claim 6, characterized in that: The S2.2 includes: Use the Galerkin method, separate the variables of the equation with the modal function, simplify it, construct the stiffness matrix, mass matrix and damping matrix of the system, and then derive the characteristic equation of the system and the expression for solving the characteristic solution.

8. A computer device, characterized in that, [[ID= 9. A computer-readable storage medium, characterized in that, ​ 10. A system for studying the effect of inner wall roughness on flow-induced vibration characteristics of a fluid delivery pipeline, characterized in that: ​ ​ Characteristic Detection Module: This module is used to obtain the characteristic solution of the fluid transmission pipeline by performing finite term superposition based on the lateral motion equation using the Galerkin method. This module also detects the flow-induced vibration characteristics of the fluid transmission pipeline based on the characteristic solution and any given operating conditions.

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