What are the functions of sound intensity method and sound pressure method in noise test of internal combustion engine?

Wind tunnel is generally called wind tunnel test. To put it simply, according to the principle of relativity of motion, the model or object of the aircraft is fixed in the artificial environment on the ground, and the artificially created airflow flows through it, thus simulating various complex flight States in the air and obtaining test data.

The main task of wind tunnel design is to provide the necessary aerodynamic environment for model tests in various speed ranges with the lowest power and cost of power plant, that is, it is hoped that various similar parameters can change in a large range in a simple wind tunnel. Wind tunnel is mainly composed of wind tunnel body, drive system and measurement control system, and the forms of each part vary with the type of wind tunnel. This cave has a test section, which can make necessary measurements and observations on the model. Upstream of the test section, there is a stable section to improve uniformity and reduce turbulence, and there is also a contraction section or nozzle to accelerate the airflow to the required speed. Downstream of the test section, there is a diffuser section to reduce the flow velocity and energy loss, and there is also a reflux section from steering flow to the exhaust section outside the wind tunnel or back to the entrance of the wind tunnel. In order to reduce the noise inside and outside the wind tunnel, silencers are often installed in the stable section and exhaust port.

NoiseXpert acoustic vibration test and analysis system can test the wind tunnel test, mainly completing the traditional measurement of sound pressure, sound intensity and vibration, and more importantly, realizing the broadband measurement and comprehensive analysis of vibration and noise based on near-field acoustic holography and acoustic focusing technology.

NoiseXpert acoustic vibration test and analysis system adopts near-field acoustic holography and acoustic focusing technology.

It can solve the following problems: inversion of surface vibration characteristics of noise source with complex vibration structure, identification and location of noise source, analysis and discrimination of noise source characteristics, and reconstruction of radiated sound field in full space; Far-field directivity prediction of sound source: test and evaluation of vibration and noise control effect; Measurement and evaluation of acoustic properties of acoustic materials.