Ripple pattern on stainless steel-lined sluice
Ripple pattern on stainless steel-lined sluice
(OP)
Think of a large sluiceway through a dam, lined with stainless steel, and subject to flow-through velocities of 20 m/s and carrying large quantities of sand and gravel. The steel surface after time has taken on a ripple-like surface erosion not unlike a sand dune pattern. Thought to be due to erosion by sand in high-intensity turbulence in the boundary layer, but are there any other thoughts? The ripples are typically about 10 mm crest to crest and a fraction of a millimetre deep, and the erosion is almost like the steel has been "stretched".





RE: Ripple pattern on stainless steel-lined sluice
RE: Ripple pattern on stainless steel-lined sluice
RE: Ripple pattern on stainless steel-lined sluice
The erosive properties of the mix can be evaluated efficiently by taking a mold of the actual erosion and evaluating the steel loss.
RE: Ripple pattern on stainless steel-lined sluice
RE: Ripple pattern on stainless steel-lined sluice
Thanks isvaaag - the turbulent "rolls" idea is what I have conceived is happening, after some surface roughness of scraping or denting was initiated by sand or gravel impacting the surface. Thereafter the turbulent BL, containing 'rolls' within circulations which result from Reynolds stress variations along the surface of the steel.
Thanks cvg. I have discounted cavitation, but thanks for the thought. My experience with cavitation damage on stainless steel is not only microscale pitting but also irregular dents in very severe (high head) conditions. The analogy with antidunes is helpful too - that is just what might be happening with sand grains eddying around in violent motion.
RE: Ripple pattern on stainless steel-lined sluice