Author(s): Kouki Onitsuka; Iehisa Nezu
Linked Author(s):
Keywords: Unsteadiness; Turbulence; Von Karman Constant; LDA; Open-Channel Flows
Abstract: The inner layer including the viscous sublayer in unsteady smooth open channel flows covering a wide range of unsteadiness were measured accurately by making use of a two-component laser Doppler anemometer (LDA). The von Karman constantκwas evaluated by making use of the friction velocity which is calculated from a linear formula. The von Karman constant decreases in the rising stage and increases in the falling stages in comparison with the value ofκ=0. 41 of steady uniform openchannel flows. Therefore, the friction velocity which is calculated by the log law deviates slightly from that calculated by the linear formula. The third order moments of the turbulence agree well with those of the steady uniform open-channel flow.
Year: 1999