A Confidence Evaluation Method for Underwater Radiated Sound Field Simulation Results

Abstract

This invention provides a method for evaluating the confidence level of underwater radiated acoustic field simulation results, by using the simulation uncertainty U S Measurement uncertainty U M Measurement results p M And simulation results p S The probability density distribution f of the difference between the measured expectation and the simulation expectation is calculated, and finally the confidence level of the error interval corresponding to the simulation result is obtained. The beneficial effects of this invention are: addressing the problem that current underwater acoustic simulation result evaluation methods do not incorporate measurement uncertainty, leading to incomplete evaluation results, this invention can provide a more comprehensive confidence evaluation result for underwater radiated sound field simulation results, providing a quantitative reference for improving underwater radiated sound field simulation, and has important implications for the development of underwater acoustic simulation technology.

Description

Technical Field

[0001] This invention relates to the field of metrology and testing, specifically to the field of acoustics (underwater acoustics), and mainly to a method for evaluating the confidence level of underwater radiated sound field simulation results. Background Technology

[0002] This invention application is based on underwater radiated noise simulation and confidence evaluation of simulation results.

[0003] With the continuous development of digital technology, the use of simulation models to assist experimental design has become an extremely common research method in the field of underwater acoustics. Constructing physical models using mathematical analytical models, finite element method, boundary element method, ray casting method, and other simulation methods to predict experimental results or directly serve as the basis for experimental design is already very common in underwater acoustic research. As the integration between simulation technology and scientific research deepens, the methods for verifying and evaluating simulation results are becoming increasingly important. Research on the evaluation methods of simulation models began systematically as early as the 1970s, and different simulation objectives and technical indicators in different research fields correspond to different simulation model evaluation methods.

[0004] Compared to other research fields, the evaluation methods for simulation models in the domestic underwater acoustics field are still in their infancy. Most domestic research on evaluation methods for underwater acoustic simulation models focuses on the reliability of simulation software and the confidence level of simulation processes, such as simulation methods. Confidence level evaluations of simulation results are mostly conducted by directly comparing simulation values ​​with test results, without considering the impact of measurement methods, measurement systems, and measurement uncertainties introduced by repeated measurements on the measurement results. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a method for evaluating the confidence of underwater radiated sound field simulation results.

[0006] The objective of this invention is achieved through the following technical solution: A method for evaluating the confidence level of underwater radiated acoustic field simulation results, comprising the following steps:

[0007] Step 1: Use the physical prototype corresponding to the simulation model to set up the test sound field;

[0008] Step 2: Input the acoustic field information related to the position of the transmitting transducer and the position of the hydrophone into the simulation model;

[0009] Step 3: Perform simulation using a simulation model to obtain the simulation result p. S and its simulation uncertainty U S ;

[0010] Step 4: Complete the physical test and obtain the measurement result p. M Its measurement uncertainty is U M ;

[0011] Step 5: Simulate the uncertainty U S Measurement uncertainty U M Measurement results p M And simulation results p S The probability density distribution f of the difference between the measured expectation and the simulation expectation is calculated, and finally the confidence level of the error interval corresponding to the simulation result is obtained.

[0012] In step 5, the probability density distribution f of the difference between the measured expectation and the simulated expectation is expressed as:

[0013]

[0014] in, To measure the uncertainty of the difference between the expected and simulated expectations, N = p M -p S f is the difference between a single measured value and a single simulated value. M To measure the probability density of the difference between the expected measured value and the true value, f S Let p0 be the probability density of the difference between the measured value and the true value under the simulation expectation, p'0 be the average value of the measurement results, and p'0 be the expected average value of the simulation results.

[0015] The beneficial effects of this invention are as follows: Addressing the problem that current underwater acoustic simulation result evaluation methods do not incorporate measurement uncertainty, leading to incomplete evaluation results, this invention proposes a confidence evaluation method for underwater radiated sound field simulation results based on measurement uncertainty. This method can provide a more comprehensive confidence evaluation of underwater radiated sound field simulation results, offering a quantitative reference for improving underwater radiated sound field simulation and significantly promoting the development of underwater acoustic simulation technology.

[0016] 1. The simulation model confidence calculation method described in this invention differs from existing methods. While comparing measurement results and simulation results, it also considers the impact of simulation uncertainty and measurement uncertainty on the evaluation of simulation results.

[0017] 2. The confidence level calculated by this patent is the integral result of the probability density function calculated by combining simulation uncertainty, measurement uncertainty, measurement result, and simulation result, rather than the ratio of simulation value to measurement value;

[0018] 3. This invention provides two descriptions of confidence calculation results: one centered on simulation results and the other centered on truth values; and provides a standard expression for describing the confidence of simulation results. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art or ordinary skills, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 The graph shows the probability density function corresponding to different values ​​of the present invention.

[0021] Figure 2 This is a schematic diagram of the confidence integral interval centered on the simulation results of the present invention.

[0022] Figure 3 This is a schematic diagram of the confidence integral interval centered on the truth value according to the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0024] This invention provides a method for evaluating the confidence level of underwater radiated sound field simulation results, based on underwater radiated noise simulation and simulation result confidence evaluation.

[0025] When measuring the sound field of a sound source at a point P, a certain measurement value is p. M The measurement uncertainty is U M Following a normal distribution, we take an α confidence interval. If the average of an infinite number of measurements is p0, which is called the measurement expectation, and all sources of measurement uncertainty have been considered in the measurement uncertainty assessment, the probability density of the difference between the measured value and the true value is f. M Then we have:

[0026]

[0027] During simulation, due to differences between the input boundary conditions and the actual measurement boundary conditions, the simulation result p... S There is also simulation uncertainty U S Following a normal distribution, an α confidence interval is used. The expected average value of the simulation results corresponding to infinitely many boundary condition inputs is denoted as p'0, which is referred to here as the simulation expectation. All sources of simulation uncertainty have been considered in the simulation uncertainty assessment, and the probability density of the difference between the measured value and the true value is f. S Then we have:

[0028]

[0029] At this point, the probability density distribution f of the difference between the measured expectation and the simulated expectation can be expressed as:

[0030]

[0031] in, To measure the uncertainty of the difference between the expected and the simulated expectations;

[0032] N = p M -p S This represents the difference between a single measurement and a single simulation.

[0033] For ease of understanding, assume a measurement was performed, and the measurement result is p. M The measurement uncertainty is 6 Pa, with a maximum pressure of 0 Pa. A simulation was performed, and the simulation result is p. S The value is 5 Pa, and the simulation uncertainty is 8 Pa; therefore, based on the measurement result and its uncertainty, and the expected value of the difference between the simulation expectation and the measurement expectation corresponding to the simulation result and its uncertainty, p′0-p0 is 5 Pa, and the uncertainty is 10 Pa. Figure 1 As shown.

[0034] If the measurement method is highly accurate, the error between the expected measurement and the true value is negligible. The confidence level for describing the result based on the simulation result is [value missing]. The probability that the simulation result differs from the true value by -5 Pa to 15 Pa is 95%. Figure 2 As shown; the description centered on the true value indicates that the probability of the true value and the simulation result differing by -5 Pa to 5 Pa is 48%, such as... Figure 3 As shown.

[0035] When describing simulation confidence, the true value is generally assumed to be the center. Therefore, the confidence of this simulation can be described as follows: the confidence level corresponding to a simulation error of ±5 Pa is 48%.

[0036] Example:

[0037] 1. Use the physical prototype corresponding to the simulation model to set up the test sound field;

[0038] 2. Input the acoustic field information, such as the position of the transmitting transducer and the position of the hydrophone, into the simulation model;

[0039] 3. Use a simulation model to perform simulation and obtain the simulation results p. S and its simulation uncertainty U S ;

[0040] 4. Complete the physical test and obtain the measurement result p. M Its measurement uncertainty is UM ;

[0041] 5. Substitute the above variables into formula (3), select the width of the integration interval U and the center of the interval N to calculate (3), and finally obtain the confidence level of the error interval corresponding to the simulation result.

[0042] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for evaluating the confidence level of underwater radiated sound field simulation results, characterized in that: The steps include the following: Step 1: Use the physical prototype corresponding to the simulation model to set up the test sound field; Step 2: Input the acoustic field information related to the position of the transmitting transducer and the position of the hydrophone into the simulation model; Step 3: Perform simulation using the simulation model and obtain the simulation results. p S and its simulation uncertainty U S ; Step 4: Complete the physical test and obtain the measurement results. p M Its measurement uncertainty is U M ; Step 5: Simulate uncertainty U S Measurement uncertainty U M Measurement results p M and simulation results p S Calculate the probability density distribution of the difference between the measured expectation and the simulation expectation. f Finally, the confidence level of the error interval corresponding to the simulation results is obtained; In step 5, the probability density distribution of the difference between the expected and simulated expectations is measured. f Represented as: in, To measure the uncertainty of the difference between the expected and the simulated expectations, N = p M - p S The difference between a single measurement value and a single simulation value. f M To measure the probability density of the difference between the expected measured value and the true value, f S Let be the probability density of the difference between the simulated value and the true value under the simulation expectation. p 0 represents the average value of the measurement results. p '0' represents the expected average value of the simulation results.

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