Supercritical Flow over a Submerged Vertical Negative Step
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 pressur...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-04-01
|
| Series: | Hydrology |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2306-5338/9/5/74 |
| _version_ | 1797499400162902016 |
|---|---|
| author | Eugene Retsinis Panos Papanicolaou |
| author_facet | Eugene Retsinis Panos Papanicolaou |
| author_sort | Eugene Retsinis |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-03-10T03:46:49Z |
| format | Article |
| id | doaj.art-d7c58a968386451d8161d9da68fc34ce |
| institution | Directory Open Access Journal |
| issn | 2306-5338 |
| language | English |
| last_indexed | 2024-03-10T03:46:49Z |
| publishDate | 2022-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Hydrology |
| spelling | doaj.art-d7c58a968386451d8161d9da68fc34ce2023-11-23T11:17:54ZengMDPI AGHydrology2306-53382022-04-01957410.3390/hydrology9050074Supercritical Flow over a Submerged Vertical Negative StepEugene Retsinis0Panos Papanicolaou1School of Civil Engineering, National Technical University of Athens, 9 Iroon Polytexneiou St., 15780 Athens, GreeceSchool of Civil Engineering, National Technical University of Athens, 9 Iroon Polytexneiou St., 15780 Athens, GreeceThe 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.https://www.mdpi.com/2306-5338/9/5/74abrupt negative stephydraulic jumpenergy lossmomentum closureBoussinesq equationsspecified intervals |
| spellingShingle | Eugene Retsinis Panos Papanicolaou Supercritical Flow over a Submerged Vertical Negative Step Hydrology abrupt negative step hydraulic jump energy loss momentum closure Boussinesq equations specified intervals |
| title | Supercritical Flow over a Submerged Vertical Negative Step |
| title_full | Supercritical Flow over a Submerged Vertical Negative Step |
| title_fullStr | Supercritical Flow over a Submerged Vertical Negative Step |
| title_full_unstemmed | Supercritical Flow over a Submerged Vertical Negative Step |
| title_short | Supercritical Flow over a Submerged Vertical Negative Step |
| title_sort | supercritical flow over a submerged vertical negative step |
| topic | abrupt negative step hydraulic jump energy loss momentum closure Boussinesq equations specified intervals |
| url | https://www.mdpi.com/2306-5338/9/5/74 |
| work_keys_str_mv | AT eugeneretsinis supercriticalflowoverasubmergedverticalnegativestep AT panospapanicolaou supercriticalflowoverasubmergedverticalnegativestep |