JET SCOUR AROUND A VERTICAL PILE

This study investigates the mechanism and the characteristic parameters affecting local scour around a vertical pile caused by turbulent circular wall jets. There are two basic scouring mechanisms: the pile obstruction and the jet diffusion mechanisms. The former is dominated by a horseshoe vortex system while the latter is controlled by the bed shear stress as the jet diffuses into the flow. Four types of equilibrium scour hole profiles were identified. The criteria for each type of profile are classified in terms of the densimetric Froude number F0 and the relative impingement distance Xi/d0. Semi-empirical equations were developed to delineate the boundary limits for the different profiles. The results show that the maximum equilibrium scour depth dse and the scour depth at the pile dpe are highly dependent of F0; and generally for large F0, dse = dpe. The scour depths are insensitive to the relative size of the pile to jet diameter D/d0. However, Xi/d0 does not appear to affect dse/d0 but it has a profound influence on dpe/d0.

• Supplemental Notes:
  • J Waterway, Port, Coastal, and Ocean Engng, v 122 n 2, March/April 1996, p 59 [9 p, 10 ref, 3 tab, 18 fig]
• Authors:
  • Chin, C O
  • Chiew, Y M
• Publication Date: 1996

Language

• English

Subject/Index Terms

• TRT Terms: Flow; Jet engines; Scour; Support piles
• Old TRIS Terms: Jet flow
• Subject Areas: Marine Transportation; Vehicles and Equipment;

Filing Info

• Accession Number: 00727774
• Record Type: Publication
• Source Agency: British Maritime Technology
• Files: TRIS
• Created Date: Nov 4 1996 12:00AM