Supercritical Flow over a Submerged Vertical Negative Step

Retsinis, Eugene; Papanicolaou, Panos

dc.contributor.author	Retsinis, Eugene
dc.contributor.author	Papanicolaou, Panos	en
dc.date.accessioned	2022-08-29T13:51:52Z
dc.date.available	2022-08-29T13:51:52Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/55562
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.23260
dc.rights	Αναφορά Δημιουργού-Μη Εμπορική Χρήση-Όχι Παράγωγα Έργα 3.0 Ελλάδα	*
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/3.0/gr/	*
dc.subject	Negative Step	en
dc.title	Supercritical Flow over a Submerged Vertical Negative Step	en
heal.type	journalArticle
heal.classification	Open Channel Hydraulics	en
heal.contributorName	Retsinis, Eugene
heal.contributorName	Papanicolaou, Panos	en
heal.language	en
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2022-04-28
heal.bibliographicCitation	Eugene Retsinis and Panos Papanicolaou, (2022). Supercritical Flow over a Submerged Vertical Negative Step, Hydrology, Special Issue: Advances in Flow Modeling for Water Resources and Hydrological Engineering, MDPI, Vol. 9, Issue 5, 74, April 2022, pp. 1-33	el
heal.abstract	The transition from supercritical to subcritical flow around a fully submerged abrupt negative step in a horizontal rectangular open channel has been investigated. In a laboratory experiment the one-dimensional energy and the momentum conservation equations were studied by means of depth and pressure measurements by piezometers installed along the bottom and the step face. Froude number varied in the range 1.9 to 5.8 while the step height to critical depth ratio was in the range 1.34 to 2.56. The results are presented in dimensionless form using mainly a characteristic length scale that is the sum of critical depth and step height and the Froude number of the supercritical flow upstream. Five different types of rapidly varying flow are observed when the subcritical downstream tailwater depth varied. The supercritical water jet at the top of the step either strikes the bottom downstream of the step when the maximum pressure head is greater, or moves to the surface of the flow when it is lower than tailwater depth, and the separation of the two flow regimes occurs when the tailwater depth to the characteristic length scale is around 1.05. The normalized energy loss and a closure parameter for the momentum equation are presented in dimensionless diagrams for practical use by the design engineer. Finally, the one-dimensional equations of motion including Boussinesq terms are solved numerically and the results found are congruent to the experimental findings.	en
heal.publisher	MDPI	en
heal.journalName	Hydrology	en
heal.journalType	peer-reviewed
heal.fullTextAvailability	false
dc.identifier.doi	https://doi.org/10.3390/hydrology9050074	el