A STUDY OF EXTERNAL AUGMENTATION OF THE VELOCITY OF FLUID JETS

In order to make tunneling operations for future transportation systems economically feasible, a new method must be developed to provide a major step forward in tunneling speed and ease of operation. Attention was directed to tunneling by water jet techniques which promise to overcome the inherent slowness of conventional tunneling methods. Previous work indicates that at high velocities, water jets produce much the same effect on rock as do explosives. A major problem of hypervelocity jet production is dealt with in this effort, that being to provide hypervelocities without requiring extremely high pressures. A new technique involving the impacting of two relatively slow-moving slugs of water to produce a very small but effective fast jet was studied by analysis and very low pressure experiments. The analysis included the effect of slug profile, prediction of fast jet velocity as a function of the slug face impact angle, fast jet mass, optimum slug length, and time between slugs. Special test fixtures were built and tested to experimentally verify the theoretical results. These tests included the high speed photography of the collapse transient, impacting of wax targets and velocity measurement by streak photography. (Author)

• Corporate Authors:

  Bowles Engineering Corporation

  Silver Spring, MD  United States 
• Publication Date: 1967

Media Info

• Pagination: 40 p.

Subject/Index Terms

• TRT Terms: Excavating equipment; Intelligent transportation systems; Mining; Tunnels
• Old TRIS Terms: Advanced systems
• Subject Areas: Bridges and other structures; Operations and Traffic Management; Railroads;

Filing Info

• Accession Number: 00039056
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: BEC-R-12-21-67
• Contract Numbers: 7-35380t
• Files: TRIS
• Created Date: Nov 24 1973 12:00AM