American Society of Civil Engineers


Scour due to Crossing Jets at Fixed Vertical Angle


by Stefano Pagliara, (corresponding author), (Professor, Dept. of Civil Engineering, Univ. of Pisa, Via Gabba 22, 56122 Pisa, Italy E-mail: s.pagliara@ing.unipi.it), Dipankar Roy, Ph.D., (Student, Dept. of Civil Engineering, Univ. of Pisa, Via Gabba 22, 56122 Pisa, Italy. E-mail: dipankar@ing.unipi.it), and Michele Palermo, Ph.D., (Dept. of Civil Engineering, Univ. of Pisa, Via Gabba 22, 56122 Pisa, Italy. E-mail: michele.palermo@ing.unipi.it)

Journal of Irrigation and Drainage Engineering, Vol. 137, No. 1, January 2011, pp. 49-55, (doi:  http://dx.doi.org/10.1061/(ASCE)IR.1943-4774.0000275)

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Document type: Journal Paper
Closure:(See full record)
Discussion: by S. K. Gupta E-mail: sunkmg@gmail.com and et al.    (See full record)
Abstract: Plunge pool scour is an important topic in hydraulic structures design. Numerous studies have been done in past years to understand the scour phenomenon due to plunging jets. These studies finally aimed at reducing the risk of structural undermining and collapse. Scour holes created under various hydraulic and geometrical conditions were analyzed for both two-dimensional and three-dimensional cases, and methods to reduce the scour were also investigated. In the current study, an attempt was made to quantify the feasibility of using crossing jets. The scour process was analyzed, and various relationships were presented to predict the main geometrical parameters, i.e., maximum scour hole depth, scour hole length, and scour hole width. Scour profiles were also compared with those due to an equivalent single jet. The main parameters on which the scour geometry depends were found as the densimetric Froude number of the jet, the crossing angle between the jets, the distance between the crossing point and the water surface level, and the water depth. All experiments have been carried out for a fixed vertical angle of 45°.


ASCE Subject Headings:
Jets (fluid)
Scour
Spillways
Tail water

Author Keywords:
Crossing jets
Plunge pool
Scour
Tailwater depth
Spillways