抄録
Observations were made on the mean and fluctuational velocities of the flow near a wall in turbulent boundary layer with non-zero pressure gradient. The edge of the sub-layer was defined as the maximum-point of the u-distribution curve. Important results obtained are as follows (suffixes 1 and 0 denoting here the values at the edge of the sub-layer and just outside the boundary layer): (i) In the field with constant pressure the curves of \barU⁄\barU1 versus y⁄δ1 are similar to those in the field with a fixed value of \barU1δ1⁄ν equal to about 165, indicating that the well-known relation between \barU⁄Uτ and yUτ⁄ν holds near the wall, Uτ being the frictional velocity; (ii) The curve of \barU⁄\barU1 varies in such a manner that ∂2(\barU⁄\barU1)⁄∂(y⁄δ1)2 increases with dP0⁄dx near the wall; (iii) The laminar sub-layer persists until the boundary layer separates and the separation of the sub-layer seems to be equivalent to turbulent separation phenomenon.
