ABSTRACT
Based on available evidence, it is hypothesized that the net force of friction on a flat solid wall, when fluid flows steadily along it, is reduced by putting one or more grooves in the wall’s surface oriented perpendicular to the mean flow. Among the convincing observations are the existence and history of golf balls which show that golf balls with dimples travel farther than golf balls without dimples. Also there is a laboratory experiment using streak photography of low Reynolds number flow along a straight wall with a square cavity in it, illustrating that the flow jumps right across the cavity’s opening, strongly suggesting that there is no friction of the fluid on the wall in the region of the cavity. One forecast is that if grooves or dimples are made on the inside surface of pipes, the discharged rate of the pipe for fluid flow should become increased.