US 2011/0256944 A1Published application

Golf ball trajectory simulation method

AssigneeBridgestone Sports Co., Ltd.

InventorKatsunori Sato

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Abstract

The invention is directed at a golf ball trajectory simulation method which sets up a golf ball model within a virtual airflow space where a grid has been generated, sets a weight for the ball model and applies initial conditions (initial velocity, launch angle, spin rate) to the ball model so as to cause the model to fly within the virtual airflow space, then calculates the lift coefficient and the drag coefficient for the golf ball from the air stream velocity, direction and pressure calculated in each grid cell, and calculates the flight distance and left-to-right dispersion for the golf ball from launch until landing by calculating, at predetermined short time intervals, the change in height, change in lateral direction, change in velocity and change in spin rate for the golf ball during flight. The trajectory simulation method divides the flight path of the golf ball model into two or three regions based on the criteria that Re=250,000 to 170,000 is a high-velocity region, Re=170,000 to 100,000 is a medium-velocity region and Re=100,000 and below is a low-velocity region, and sets up short time intervals Δta in the high-velocity region, short time intervals Δtb in the medium-velocity region and short time intervals Δtc in the low-velocity region such that Δta>Δtb>Δtc.

Claims14

Dependent claims

A golf ball trajectory simulation method which employs arithmetic operations executed by a computer to analyze and estimate the trajectory of a golf ball having a plurality of dimples on a surface thereof when the ball is launched into flight, comprising the steps of:

(A) generating a grid within a virtual airflow space (field) where the ball is to be launched;
(B) setting up within the virtual airflow space (field) a substantially spherical golf ball model having a plurality of dimples formed on a surface thereof;
(C) dividing the grid into cells in such a way as to make the grid near the golf ball model finer than the grid within the virtual space (field) and to have the grid gradually increase in size in a direction leading away from the surface of the ball model;
(D) setting a weight for the golf ball model;
(E) applying initial conditions (initial velocity, launch angle, spin rate) to the golf ball model;
(F) initiating movement of the golf ball model under the initial conditions, regenerating in an area of movement the grid near the ball in such a way as to follow the movement of the ball model without disturbing the originally set grid size, and restoring the grid after the ball has passed therethrough to the grid within the virtual airflow space (field);
(G) calculating a lift coefficient and a drag coefficient for the golf ball in flight within the virtual airflow space (field) by integrating an air stream velocity, direction and pressure calculated in each grid cell within the virtual airflow space (field);
and
(H) calculating a flight distance and a left-to-right dispersion for the golf ball from launch until landing by calculating, at predetermined short time intervals, a change in height, a change in lateral direction, a change in velocity and a change in spin rate for the golf ball during flight,
wherein the simulation method, when estimating the trajectory, calculates the Reynolds number (Re) around the golf ball model in flight, divides a flight path of the golf ball model into two or three regions based on the criteria that Re=250,000 to 170,000 is a high-velocity region, Re=170,000 to 100,000 is a medium-velocity region and Re=100,000 and below is a low-velocity region, and sets up short time intervals Δta in the high-velocity region, short time intervals Δtb in the medium-velocity region and short time intervals Δtc in the low-velocity region such that Δta>Δtb>Δtc.

7 more elements

A golf ball trajectory simulation method that employs arithmetic operations executed by a computer to analyze and estimate a trajectory of a golf ball having a plurality of dimples on a surface thereof when the ball is launched into flight, comprising the steps of:

(A) generating a grid within a virtual airflow space (field) where the ball is to be launched;
(B) setting up within the virtual airflow space (field) a substantially spherical golf ball model having a plurality of dimples formed on a surface thereof;
(C) dividing the grid into cells in such a way as to make the grid near the golf ball model finer than the grid within the virtual space (field) and to have the grid gradually increase in size in a direction leading away from the surface of the ball model;
(D) setting a weight for the golf ball model;
(D-2) setting up within the virtual airflow space a state wherein an air stream of a given velocity flows into the golf ball model;
(E) applying initial conditions (initial velocity, launch angle, spin rate) to the golf ball model;
(F) initiating movement of the golf ball model under the initial conditions, regenerating in an area of movement the grid near the ball in such a way as to follow the movement of the ball model without disturbing the originally set grid size, and restoring the grid after the ball has passed therethrough to the grid within the virtual airflow space (field);
(G) calculating a lift coefficient and a drag coefficient for the golf ball in flight within the virtual airflow space (field) by integrating an air stream velocity, direction and pressure calculated in each grid cell within the virtual airflow space (field);
and
(H) calculating a flight distance and a left-to-right dispersion for the golf ball from launch until landing by calculating, at predetermined short time intervals, a change in height, a change in lateral direction, a change in velocity and a change in spin rate for the golf ball during flight, wherein the simulation method, when estimating the trajectory, calculates the Reynolds number (Re) around the golf ball model in flight, divides a flight path of the golf ball model into two or three regions based on the criteria that Re=250,000 to 170,000 is a high-velocity region, Re=170,000 to 100,000 is a medium-velocity region and Re=100,000 and below is a low-velocity region, and sets up short time intervals Δta in the high-velocity region, short time intervals Δtb in the medium-velocity region and short time intervals Δtc in the low-velocity region such that Δta>Δtb>Δtc.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/972,982Filed 20 Dec 2010
Priority: 20 Apr 2010
Published: 20 Oct 2011
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

G06F 30/28
Design optimisation, verification or simulation: using fluid dynamics, e.g. using Navier-Stokes equations or computational fluid dynamics [CFD]
A63B 69/36
Training appliances or apparatus for special sports: for golf
G06F 30/20
Computer-aided design [CAD]: design optimisation, verification or simulation
G06F 30/23
Design optimisation, verification or simulation: using finite element methods [FEM] or finite difference methods [FDM]

Family

Application12/763,425Continuation in part · filed 20 Apr 2010
Application12/972,982Continuation in part
US 2011/0040535 A1Published application
US 8,452,575 B2Related patent
US 2011/0256944 A1This patent

From the US filing history. Foreign family members aren’t listed.