Golfball

A golf ball is a game device in the Gulf.

Features and Construction

The size and texture of a golf ball are defined in the Rules of Golf. The diameter of a golf ball is at least 42.67 mm, the maximum weight at 45.93 g The surface of the ball is provided with approximately 300 to 450 small dents ( so-called Dimples ). The exact number of " Dimples " is not defined. It has almost every maker has a different arrangement of the dimples, which are intended to optimize the trajectory.

A golf ball is made of a hard plastic shell ( in the past was used gutta-percha ) with different cores. In addition to hard rubber cores and multi- layer cores of various flexible materials are increasingly being used. Depending on the number of the different layers is referred to as 2- piece, 3 - piece, 4 - piece (and so on ) balls. On most golf balls, a number is printed. This serves to distinguish the ball of balls of other players when a ball of the same brand and same type of use.

The golf ball is in play

It has become common to say in front of the first tee, both brand and type and number of the ball. Once the ball must be replaced regularly compliant, even this information should be passed on to other players. This procedure is a label and not a rule question.

Physics

The trajectory of a golf ball is determined by the force of gravity and aerodynamic forces.

Due to the angle of the club head at impact, the ball is put into rotation, which contributes to the necessary direction during the flight stability. Every golf shot triggers a backspin, if the ball is hit to the face. The different trajectories are triggered by additional Seitrotationen.

The dimples on the ball surface to reduce the drag coefficient by decreasing the pressure resistance, and reduce the air resistance by up to 50 %. Depending on the stroke technique of the player, a golf ball fly up to four times more.

The diameter and the speed of a golf ball are so low that the Reynolds number is small suggests a laminar boundary layer flow. Small eddies within the dimples change the laminar boundary layer around the ball in a turbulent boundary layer. The flow separates from delays, thus reducing the volume of the dead-water zone. In this area there is a negative pressure. The smaller the zone, the lower the pressure difference to the upstream side, and thus the retardation in the direction of flight. On the same principle is the operation of the turbulators in the airfoil is smaller aircraft. The graph shows the effect of air friction on the flight distance. At a discount rate of 80m / s, a golf ball without air friction (Cw = 0) would fly more than 600 meters wide. Without Dimples the drag coefficient is about 0.4, which corresponds to a gap distance of 150 m. With Dimples (Cw = 0.1 ) it increases to more than double.

There are hundreds of different Dimplemuster that are developed by the respective manufacturers of golf balls.

Golf balls are elastic. The so-called Smash save on contact with the bat energy they give back the tee. The Smash contributes to increase the speed of the ball. Good golf ball players reach speeds of 250 km / hr, the record is at 328 km / h