Object shape determining method

• US 6,285,968 B1
• Filed: 07/09/1998
• Issued: 09/04/2001
• Est. Priority Date: 07/11/1997
• Status: Expired due to Fees

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Arima, Toshiyuki, Shirotori, Masatoshi, Motoyama, Keiichi
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): FREJD, RUSSELL WARREN
• Application Number:
  US09/112,928
• Time in Patent Office: 1,153 Days
• Field of Search: 703/1, 703/2, 703/9, 702/140, 702/138, 702/100, 702/12
• US Class Current: 703/1
• CPC Class Codes: G06F 2111/10 Numerical modelling
• CPC Class Codes: G06F 30/23 using finite element methods [FEM] or finite difference methods [FDM]

Abstract

An initial object shape is set in a first process, a numeric fluid dynamic grid is generated on the surface of the object shape in a second process, and Navier-Stokes equations are numerically solved by numerical fluid dynamics based on the object and the grid generated with the object shape and an object surface pressure is determined in a third process. The noise generated by the object is a determined in a fourth process, by solving Curle'"'"'s formula based on the object surface pressure, and noises are again determined in a fifth process by updating the object shape and repeating the first through fourth processes. By determining an object shape based on a shape which generates the smallest noise from among the noises determined by the fifth process, it becomes possible to determine a shape of the object as a shape capable of minimizing aerodynamic noise generated upon movement of the object through a fluid medium.

Claims

1. A method of using a processor to receive signals from an input device providing an object shape by performing operations for determining the object shape that minimizes aerodynamic noise generated upon movement of the object through a fluid medium, comprising:

a first step of setting an initial object shape;

a second step of generating a numerical fluid dynamic grid on a surface of the object shape;

a third step of numerically solving, by numerical fluid dynamics, Navier-Stokes equations based on the grid generated with the object shape and the object, and determining a pressure of the object surface;

a fourth step of determining noise generated by said object by solving Curle'"'"'s formula based on the pressure of the object surface; and

a fifth step of updating the object shape while repeating said first through fourth steps and determining the noise thereof,

wherein the shape of said object is determined based on a shape which generates the smallest noise from among the noises determined in said fifth step.

2. The object shape determining method according to claim 1, wherein updating of said object shape in said fifth step is based on genetic algorithms.

3. The object shape determining method according to claim 2, wherein the genetic algorithms are based on an elitism strategy, in which optimum individuals of each generation are reproduced and remain in successive generations.

4. A method of using a processor to receive signals from an input device providing an object shape by performing operations for determining the object shape that minimizes aerodynamic noise generated upon movement of the object through a fluid medium, comprising:

a first step of setting a parameter for successively varying and specifying an initial object shape and an object shape;

a second step of generating a numerical fluid dynamic grid on a surface of the object shape;

a third step of numerically solving, by numerical fluid dynamics, Navier-Stokes equations based on the grid generated with the object shape and the object, and determining a pressure of the object surface;

a fourth step of determining noise generated by said object by solving Curle'"'"'s formula based on the pressure of the object surface; and

a fifth step of updating said parameter and varying said object shape while repeating said first through fourth steps and determining the noise thereof;

wherein the shape which generates the smallest noise from among the noises determined in said fifth step is determined based on the initial shape and said parameter.

5. The object shape determining method according to claim 4, wherein updating of said object shape in said fifth step is based on genetic algorithms.

6. The object shape determining method according to claim 5, wherein the genetic algorithms are based on an elitism strategy, in which optimum individuals of each generation are reproduced and remain in successive generations.