{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,16]],"date-time":"2025-11-16T06:08:42Z","timestamp":1763273322645},"reference-count":27,"publisher":"ASME International","issue":"6","content-domain":{"domain":["asmedigitalcollection.asme.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2006,11,1]]},"abstract":"<jats:p>The development of the roller-compacted concrete (RCC) as a technique of constructing dams and the stepped surface that results from the construction procedure opened a renewed interest in stepped spillways. Previous research has focused on studying the air-water flow down the stepped chute with the objective of obtaining better design guidelines. The nonaerated flow region enlarges as the flow rate increases, and there is a lack of knowledge on the hydraulic performance of stepped spillways at high velocities that undermines its use in fear of cavitation damage. In the present, study the developing flow region in a stepped channel with a slope 1v:0.8h is characterized using a particle image velocimetry technique. An expression for the growth of the boundary layer thickness is proposed based on the streamwise distance from the channel crest and the roughness height. The local flow resistance coefficient is calculated by application of the von K\u00e1rm\u00e1n integral momentum equation. The shear strain, vorticity, and swirling strength maps obtained from the mean velocity gradient tensor are presented. Also, the fluctuating velocity field is assessed. The turbulent kinetic energy map indicates the region near the pseudobottom (imaginary line joining two adjacent step edges) as the most active in terms of Reynolds stresses. The turbulence was found to be very intense with maximum levels of turbulence intensity from 0.40 to 0.65 measured near the pseudobottom. Finally, the quadrant analysis of the velocity fluctuations suggests the presence of strong outflows of fluid from the cavities as well as inflows into the cavities. It is conjectured that the mass transfer\/exchange between cavities and main stream, play an important role in the high levels of turbulent energy observed.<\/jats:p>","DOI":"10.1115\/1.2354529","type":"journal-article","created":{"date-parts":[[2006,10,20]],"date-time":"2006-10-20T22:28:24Z","timestamp":1161383304000},"page":"1266-1273","update-policy":"http:\/\/dx.doi.org\/10.1115\/crossmarkpolicy-asme","source":"Crossref","is-referenced-by-count":67,"title":["Characterization of the Nonaerated Flow Region in a Stepped Spillway by PIV"],"prefix":"10.1115","volume":"128","author":[{"given":"Ant\u00f3nio","family":"Amador","sequence":"first","affiliation":[{"name":"Hydraulic and Environmental Department., Technologic School of Barreiro, IPS, R. Stinville No. 14 Quimiparque, Barreiro 2830-144, Portugal"}]},{"given":"Mart\u00ed","family":"S\u00e1nchez-Juny","sequence":"additional","affiliation":[{"name":"Hydraulic, Maritime and Environmental Department, Polythecnic University of Catalonia (UPC), C. Jordi Girona Campus Nord 1\/3 Ed. D1, Barcelona 08034, Spain"}]},{"given":"Josep","family":"Dolz","sequence":"additional","affiliation":[{"name":"Hydraulic, Maritime and Environmental Department, Polythecnic University of Catalonia (UPC), C. Jordi Girona Campus Nord 1\/3 Ed. D1, Barcelona 08034, Spain"}]}],"member":"33","published-online":{"date-parts":[[2006,4,7]]},"reference":[{"key":"2019100514333744500_c1","unstructured":"Essery, I., and Horner, M., 1978, \u201cThe Hydraulic Design of Stepped Spillways,\u201d CIRIA Report No. 33, London, 2nd ed."},{"key":"2019100514333744500_c2","volume-title":"Hydraulic Design of Stepped Cascades, Channels, Weirs and Spillways","author":"Chanson"},{"key":"2019100514333744500_c3","doi-asserted-by":"crossref","volume-title":"The Hydraulics of Stepped Chutes and Spillways","author":"Chanson","DOI":"10.1115\/1.1523365"},{"key":"2019100514333744500_c4","doi-asserted-by":"publisher","first-page":"33","DOI":"10.1139\/l03-066","article-title":"Interactions Between Cavity Flow and Main Stream Skimming Flow: an Experimental Study","volume":"31","author":"Gonzalez","journal-title":"Can. J. Civ. 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Technol.","ISSN":"http:\/\/id.crossref.org\/issn\/0957-0233","issn-type":"print"},{"key":"2019100514333744500_c13","first-page":"236","article-title":"Efficient Detection of Spurious Vectors in Particle Image Velocimetry","volume":"16","author":"Westerweel","journal-title":"Exp. Fluids","ISSN":"http:\/\/id.crossref.org\/issn\/0723-4864","issn-type":"print"},{"key":"2019100514333744500_c14","doi-asserted-by":"crossref","first-page":"310","DOI":"10.1007\/s003480050355","article-title":"On the Accuracy of a MJPEG-Based Digital Compression PIV-System","volume":"27","author":"Freek","journal-title":"Exp. Fluids","ISSN":"http:\/\/id.crossref.org\/issn\/0723-4864","issn-type":"print"},{"key":"2019100514333744500_c15","doi-asserted-by":"crossref","first-page":"587","DOI":"10.1061\/(ASCE)0733-9429(1990)116:4(587)","article-title":"Skimming Flow in Stepped Spillways","volume":"116","author":"Rajaratnam","journal-title":"J. Hydraul. Eng.","ISSN":"http:\/\/id.crossref.org\/issn\/0733-9429","issn-type":"print"},{"key":"2019100514333744500_c16","unstructured":"U.S. Bureau of Reclamation, 1977, Hydraulic Design Criteria-Sheet 111-18 to 111-18\/5, Corps of Engineers, USA."},{"key":"2019100514333744500_c17","doi-asserted-by":"crossref","volume-title":"Turbulent Flows","author":"Pope","DOI":"10.1017\/CBO9780511840531"},{"key":"2019100514333744500_c18","doi-asserted-by":"publisher","first-page":"271","DOI":"10.1017\/S0022112099005911","article-title":"The Turbulent Boundary Layer Over Transverse Square Cavities","volume":"395","author":"Djenidi","journal-title":"J. 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