WIND NOISE ANALYZER AND WIND NOISE ANALYSIS METHOD

• US 20190331510A1
• Filed: 04/22/2019
• Published: 10/31/2019
• Est. Priority Date: 04/27/2018
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: PHAN, Long Vinh
• Granted Patent: US 11,544,421 B2
• Time in Patent Office: Days
• CPC Class Codes: G01F 1/206 Measuring pressure, force or momentum of a fluid flow which is forced to change its direction
• CPC Class Codes: G01F 1/3282 for detecting variations in infrasonic, sonic or ultrasonic waves, due to modulation by passing through the swirling fluid
• CPC Class Codes: G01M 9/08 Aerodynamic models
• CPC Class Codes: G06F 2119/10 Noise analysis or noise optimisation
• CPC Class Codes: G06F 30/15 Vehicle, aircraft or watercraft design
• CPC Class Codes: G06F 30/20 Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30
• CPC Class Codes: G06F 30/28 using fluid dynamics, e.g. using Navier-Stokes equations or computational fluid dynamics [CFD]
• CPC Class Codes: Y02T 90/00 Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation

Abstract

A wind noise analyzer includes: an unsteady computational fluid dynamics calculation unit configured to execute an unsteady computational fluid dynamics simulation involving moving a structure model modeled on a structure, and calculate, for each of spatial nodes, an average flow velocity and an average vorticity over a predetermined time in a flow field inside the predetermined region, and then calculate, for each of the spatial nodes, a value based on an amplitude of a turbulent flow velocity inside the predetermined region, in an angular frequency band of interest; and a pressure source density calculation unit configured to calculate, based on the average flow velocity, the average vorticity, and the value based on the amplitude of the turbulent flow velocity, a pressure source density.

Claims

1. A wind noise analyzer comprising:

an unsteady computational fluid dynamics calculation unit configured to;

execute an unsteady computational fluid dynamics simulation involving moving a structure model modeled on a structure, and calculate, for each of spatial nodes that are nodes inside a predetermined region of a flow field around the structure model, an average flow velocity and an average vorticity over a predetermined time in a flow field inside the predetermined region; and

calculate, for each of the spatial nodes, a value based on an amplitude of a turbulent flow velocity inside the predetermined region, in an angular frequency band of interest that is a target angular frequency band of a wind noise analysis; and

a pressure source density calculation unit configured to calculate, based on the average flow velocity, the average vorticity, and the value based on the amplitude of the turbulent flow velocity calculated by the unsteady computational fluid dynamics calculation unit, a pressure source density that is an indicator of a degree of contribution of a flow field at a spatial node inside the predetermined region to a surface pressure fluctuation that is an amplitude of a pressure fluctuation at an analysis target point of the wind noise in a surface of the structure model.

2. The wind noise analyzer according to claim 1, wherein a value obtained by spatially integrating the pressure source density at the analysis target point in the surface of the structure model with respect to the predetermined region is an approximate value of a value obtained by integrating a product of a function of the surface pressure fluctuation at the analysis target point and a complex conjugate function of that function with respect to the angular frequency band of interest.

3. The wind noise analyzer according to claim 1, further comprising a causal parameter identification unit that identifies a causal parameter that is a parameter contributing relatively significantly to the pressure source density among a plurality of parameters composing the pressure source density.

4. The wind noise analyzer according to claim 3, wherein the parameters are the average flow velocity, the average vorticity, and the turbulent flow velocity.

5. The wind noise analyzer according to claim 1, further comprising an image processing unit configured to:

extract, from a plurality of spatial nodes for which the pressure source density has been calculated, a plurality of spatial nodes corresponding to a pressure source density having a value input from outside;

create a plane of equivalent values by performing image processing on the spatial nodes extracted; and

visualize the plane of equivalent values.

6. The wind noise analyzer according to claim 1, further comprising a spatial node extraction unit configured to extract a spatial node corresponding to a maximum value of a plurality of pressure source densities calculated by the pressure source density calculation unit.

7. The wind noise analyzer according to claim 1, wherein the unsteady computational fluid dynamics calculation unit is configured to calculate, for each of surface nodes that are nodes on a surface of the structure model, the surface pressure fluctuation on the surface in the angular frequency band of interest.

8. The wind noise analyzer according to claim 1, wherein a calculation formula of the pressure source density is defined by a following expression:

9. A wind noise analysis method comprising:

executing an unsteady computational fluid dynamics simulation involving moving a structure model modeled on a structure, and calculating, for each of spatial nodes that are nodes inside a predetermined region of a flow field around the structure model, an average flow velocity and an average vorticity over a predetermined time in a flow field inside the predetermined region, and then calculating, for each of the spatial nodes, a value based on an amplitude of a turbulent flow velocity inside the predetermined region, in an angular frequency band of interest that is a target angular frequency band of a wind noise analysis; and

calculating, based on the average flow velocity, the average vorticity, and the value based on the amplitude of the turbulent flow velocity, a pressure source density that is an indicator of a degree of contribution of a flow field at a spatial node inside the predetermined region to a surface pressure fluctuation that is an amplitude of a pressure fluctuation at a target point of the wind noise analysis in a surface of the structure model.