Method used for predicting ground sound field of helicopter rotor

A helicopter rotor and ground technology, applied in the field of helicopters, can solve the problems of not considering the influence of noise propagation characteristics, time-consuming calculation time, etc., to achieve the effect of improving accuracy and reducing calculation time

Inactive Publication Date: 2016-04-06
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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Problems solved by technology

In the actual helicopter noise assessment, there are many flight states, so the calculation time is very time-consuming
[0004] In addition, the existing ground sound field prediction methods do not consider the influence of the atmosphere, ground and other environmental factors on the noise propagation characteristics during the real flight of the helicopter.
Therefore, the estimated result of the noise will be quite different from the actual result

Method used

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  • Method used for predicting ground sound field of helicopter rotor
  • Method used for predicting ground sound field of helicopter rotor
  • Method used for predicting ground sound field of helicopter rotor

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Experimental program
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Embodiment

[0031] This implementation uses the AH-1 / OLS test rotor.

[0032] The method for helicopter rotor ground sound field prediction of the present invention comprises the following steps:

[0033] The first step is to input the calculation state parameters. The calculation state parameters used in this part are: tension coefficient 0.0054, forward ratio 0.164, collective distance 6.2°, vertical and horizontal periodic pitches are -2.4° and 1.0° respectively.

[0034] The second step is to calculate the second-level acoustic radiation sphere at a radius of 25R from the center of the rotor hub of the AH-1 rotor in this state, and the noise observation points on the acoustic radiation sphere are distributed at equal angular intervals (interval 5°) along the direction of blade rotation and elevation angle . The noise at the observation point is solved using the free wake / FW-H equation; the above two processes complete the pre-calculation of the ground sound field prediction.

[0035...

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Abstract

The invention discloses a method used for predicting a ground sound field of a helicopter rotor, and is used for simulating influence on the ground sound field by rotor noise in a helicopter flight process. The method comprises the following steps: carrying our rotor aerodynamic load calculation, designing and calculating a second-level acoustic radiation ball, carrying out ground observation region point dispersion, establishing a noise propagation model, and calculating the ground sound field. The method disclosed by the invention can greatly shorten time for calculating the influence on the ground by the rotor noise on the basis of a traditional direct calculation method. Since the method establishes the noise propagation model which considers the influence on noise propagation characteristics by environmental factors including atmosphere, ground and the like, compared with the traditional method, the method disclosed by the invention can obviously improve result prediction accuracy.

Description

technical field [0001] The invention belongs to the technical field of helicopters, in particular to a method for efficiently predicting the ground sound field of a helicopter rotor, which is used for simulating the influence of rotor noise on the ground sound field during helicopter flight. Background technique [0002] With the wide application of helicopters, the disadvantage of high noise has attracted more and more people's attention, and has become the main limiting factor for its further application in the military and civilian fields. Therefore, the establishment of a prediction method that can quickly evaluate the impact of noise on the ground during helicopter flight plays an important role in supporting the helicopter's finalization, airworthiness, and noise reduction during use. [0003] At present, the ground sound field prediction can only use the "direct calculation method", that is, firstly calculate the flow field of the rotor to obtain the load information ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50
CPCG06F30/367Y02T90/00
Inventor 史勇杰王菲徐国华
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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