An investigation of turbulent flow in a corrugated pipe

Today turbulent measurement with hot wire anemometer is a routine procedure but the conventional equations require a knowledge of the direction of the mean velocity. For flow over peripheral corrugations where the mean velocity vector is changing in direction with radial and axial positions the conventional equations are not valid. Therefore, new equations were derived. These show that the simple sum and differencing techniques useful for parallel flow no longer can be applied. Experiments were made in a corrugated pipe. This corrugated pipe approximates a sine wave in shape and has the wavelength, 2.75", the amplitude, 0.437", and the smallest radius, 4.275". Experimental data shows that the conventional commercial X-wire boundary layer probe support system interference to the flow. A special type of X-wire was designed and called "Boundary Layer Probe." Using this probe, the radial velocity vector can be easily determined along with the axial component from the derived equations. The system of equations is complex requiring computer solution of data digitized from analog tape. Data show that the turbulent Intensities in longitudinal and radial direction across the pipe radius are higher than those measured from the smooth circular pipe. This is so even at the centerline. The local relative turbulent intensities show that a sharp jump occurs around the tip line (line connecting the tips of the peaks) at certain section which seems to indicate a "separation flow" existing in that region.