Underwater radiation sound field simulation result confidence evaluation method

Abstract

The invention provides an underwater radiation sound field simulation result confidence evaluation method, which comprises the following steps of: calculating probability density distribution f of a difference between measurement expectation and simulation expectation through simulation uncertainty US, measurement uncertainty UM, a measurement result pM and a simulation result pS, and finally obtaining confidence of an error interval corresponding to the simulation result. The method has the beneficial effects that aiming at the problem that the evaluation result is incomplete due to the fact that the measurement uncertainty is not introduced in the current underwater sound simulation result evaluation method, the confidence evaluation result of the underwater radiation sound field simulation result can be comprehensively given, and quantitative reference is provided for improvement of underwater radiation sound field simulation; and the method has important promotion significance on the development of an underwater sound simulation technology.

Description

Technical Field

[0001] The invention relates to the field of measurement and testing, in particular to the field of acoustics (hydroacoustics), and mainly relates to a confidence evaluation method for underwater radiation sound field simulation results. Background Art

[0002] The application of the present invention is based on the background of underwater radiation noise simulation and simulation result confidence evaluation.

[0003] With the continuous development of digital technology, the use of simulation models to assist experimental design in the field of underwater acoustics is currently a very common scientific research method. It is very common in underwater acoustic research to use mathematical analytical solution models, finite elements, boundary elements, ray methods and other simulation methods to construct physical models to predict test results or directly use them as the basis for experimental design. With the continuous deepening of the integration of simulation technology and scientific research work, the verification and evaluation methods of simulation results are becoming more and more important. The study of evaluation methods for simulation models has been systematically carried out as early as the 1970s. Different simulation goals and different technical indicators in different scientific research fields correspond to different simulation model evaluation methods.

[0004] Compared with other scientific research fields, the evaluation methods of simulation models in the field of underwater acoustics in China are still in their infancy. Most of the research on the evaluation methods of underwater acoustic simulation models in China focuses on the confidence evaluation of the simulation process, such as the reliability of simulation software and simulation methods. The confidence evaluation of simulation results is mostly carried out by directly comparing the simulation values ​​with the test results, without considering the impact of the measurement uncertainty introduced by the measurement method, measurement system, and repeated measurements on the measurement results. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a confidence evaluation method for underwater radiated sound field simulation results.

[0006] The objective of the present invention is achieved through the following technical solution: A confidence evaluation method for underwater radiated sound field simulation results, comprising the following steps:

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

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

[0009] Step 3: Use the simulation model to simulate and obtain the simulation result p S and its simulation uncertainty U S ;

[0010] Step 4: Complete the physical test and get the measurement result p M And its measurement uncertainty is U M ;

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

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

[0015] The beneficial effects of the present invention are as follows: in view of the problem that the current underwater acoustic simulation result evaluation method does not introduce measurement uncertainty, resulting in incomplete evaluation results, the present invention proposes a confidence evaluation method for underwater radiation sound field simulation results based on measurement uncertainty, which can give a relatively comprehensive confidence evaluation result of the underwater radiation sound field simulation result, provide a quantitative reference for the improvement of underwater radiation sound field simulation, and have an important promoting significance for the development of underwater acoustic simulation technology.

[0016] 1. The simulation model confidence calculation method described in the present invention is different from the existing method. While comparing the measurement results and the simulation results, it also considers the influence of the simulation uncertainty and the measurement uncertainty on the evaluation of the simulation results;

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

[0018] 3. The present invention provides two descriptions of confidence calculation results, one centered on simulation results and the other centered on true values; and provides a standard expression for describing the confidence of simulation results. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use 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 technicians, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is the probability density function diagram corresponding to different values ​​of the present invention.

[0021] Figure 2 It is a schematic diagram of the confidence integration interval centered on the simulation result of the present invention.

[0022] Figure 3 It is a schematic diagram of the confidence integration interval centered on the true value of the present invention. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0024] The invention is based on the background of underwater radiation noise simulation and simulation result confidence evaluation, and provides a method for evaluating the confidence of underwater radiation sound field simulation results.

[0025] When measuring the sound field of a sound source at a certain point P, the measurement value at a certain time is p M , the measurement uncertainty is U M , follow the normal distribution, and take the α confidence interval. If the average value of the infinite number of measurement results is p0, which is called the measurement expectation here, and all sources of measurement uncertainty components 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:

[0026]

[0027] During the simulation, due to the certain differences between the input boundary conditions and the boundary conditions during the actual measurement, the simulation results p S There is also a simulation uncertainty U S , following the normal distribution, taking the α confidence interval. The average expected value of the simulation results corresponding to the infinite boundary condition input is set to p'0, which is called the simulation expectation here. In the simulation uncertainty assessment, all sources of simulation uncertainty components have been considered. The probability density of the difference between the measured value and the true value is f S , then:

[0028]

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

[0030]

[0031] in, is the uncertainty of the difference between the measured expectation and the simulated expectation;

[0032] N=p M -p S It is the difference between a single measurement value and a single simulation value.

[0033] For ease of understanding, assume that a measurement is made and the measurement result p M is 0Pa, and the measurement uncertainty is 6Pa; a simulation was performed, and the simulation result p S is 5Pa, and the simulation uncertainty is 8Pa; then the expected p′0-p0 of the difference between the simulation expectation and the measurement expectation corresponding to the measurement result and its uncertainty this time and the simulation result and its uncertainty this time is 5Pa, and the uncertainty is 10Pa, such as Figure 1 shown.

[0034] If the measurement method is very accurate, the error between the expected measurement and the true value can be ignored. The confidence level of the simulation result is 95%, and the probability that the simulation result and the true value differ by -5Pa to 15Pa is 95%. Figure 2 As shown; the description centered on the true value is that the probability that the true value and the simulation result differ by -5Pa to 5Pa is 48%, as Figure 3 shown.

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

[0036] Example:

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

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

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

[0040] 4. Complete the physical test and get the measurement result p M And its measurement uncertainty is UM ;

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

[0042] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A confidence evaluation method for underwater radiated sound field simulation results, characterized in that: The steps include: Step 1: Use the physical prototype corresponding to the simulation model to arrange the test sound field; Step 2: Input the acoustic field information related to the transmitting transducer position and the hydrophone position into the simulation model; Step 3: Use the simulation model to simulate and obtain the simulation result p S and its simulation uncertainty U S ; Step 4: Complete the physical test and get the measurement result p M And its measurement uncertainty is U M ; Step 5: Simulate the uncertainty U S , measurement uncertainty U M , measurement results p M And the simulation results p S , calculate the probability density distribution f of the difference between the measured expectation and the simulation expectation, and finally obtain the confidence level of the error interval corresponding to the simulation result.

2. The confidence evaluation method for underwater radiated sound field simulation results according to claim 1, characterized in that: In step 5, the probability density distribution f of the difference between the measured expectation and the simulated expectation is expressed as: in, is the uncertainty of the difference between the measured expectation and the simulated expectation, N = p M -p S is the difference between a single measurement value and a single simulation value, f M is the probability density of the difference between the measured value and the true value under the measurement expectation, f S is the probability density of the difference between the measured value and the true value under simulation expectation, p0 is the average value of the measurement results, and p'0 is the expected average value of the simulation results.

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