Investigating similarity in turbulent jets by LDA

In this paper, a proof of the existence of the similarity in simple round and coaxial jets is given for nondimensional mean velocity and for turbulence. This proof is based on experimental investigation and analysis of mean velocity and turbulent profiles in simple round or coaxial free jets obtained from DISA 55x two-dimensional Laser Doppler Anemometry (LDA). It is concluded that: LDA can be used to investigate the similarity of isobaric compressible and incompressible jets. The similarity curve of the mean velocity and the root mean square of the turbulence are insensitive to thickness of nozzle lips and Re number.