抄録
Measurements by a laser doppler velocimeter have become essential to the examination of the behavior of gas in the cylinders of an internal-combustion engine. As the measurements demand a considerable level of technique, however, I have made as the first step the velocity distribution measurements outside the inlet length of water flow in a round pipe by using a laser doppler velocimeter, Through the measurements I have obtained pretty excellent results: errors came within approximately 3 percent in either case of laminar flow, transition flow or turbulent flow, and the turbulence levels within 3.5 percent in the turbulent zone of Re no. 11200.
