Search results for "Rectangular channel"

Convective Instability in a Horizontal Porous Channel with Permeable and Conducting Side Boundaries

2013

Published version of an article in the journal: Transport in Porous Media. Also available on Science Direct: http://dx.doi.org/10.1007/s11242-013-0198-y The stability analysis of the motionless state of a horizontal porous channel with rectangular cross-section and saturated by a fluid is developed. The heating from below is modelled by a uniform flux, while the top wall is assumed to be isothermal. The side boundaries are considered as permeable and perfectly conducting. The linear stability of the basic state is studied for the normal mode perturbations. The principle of exchange of stabilities is proved, so that only stationary normalmodes need to be considered in the stability analysis.…

Sequent Depth Ratio of a B-Jump

2011

A B-jump is defined as the jump having the toe section located on a positively sloping upstream channel and the roller end on a downstream horizontal channel. This jump often occurs in the stilling basins with a horizontal bottom and located downstream of a steep channel. For a B-jump, a completely theoretical approach is not sufficient to solve the momentum equation and to establish the sequent depth ratio. In this paper, by using the laboratory measurements carried out in this investigation, some available empirical relationships useful for estimating the sequent depth ratio are tested. Then, by using the Π theorem of the dimensional analysis and the incomplete self-similarity theory, a g…

Hydraulic jumps at drop and abrupt enlargement in rectangular channel

2002

The different types of hydraulic jumps that occur in a rectangular channel at an abrupt increase in section are experimentally studied. The abrupt section increase is due to both a drop and an increase in the channel width. Experiments were carried out with three different values of the ratio L/l between the channel widths respectively downstream and upstream of the abrupt section increase. For each L/l value five values of Froude number F1, of the supercritical flow upstream of the section increase were considered, and for each of them live values of the depth y1 of the same flow. The experiments showed that, as the depth y2 of the downstream subcritical flow increases, several types of hy…

Closure to “Sequent Depth Ratio of a B-Jump” by Francesco Giuseppe Carollo, Vito Ferro, and Vincenzo Pampalone

2013

Explicit equations for uniform flow depth

2017

Conventional approach in uniform open channel flow is to express the resistance coefficient in the Manning, Darcy-Weisbach or Chezy form. However, for practical cross-sections, including rectangular and trapezoidal ones, the governing equation is implicit in the uniform water depth. For these sections the water depth, corresponding to known values of the flow discharge, slope channel and resistance coefficient, is presently obtained by trial and error procedure. In this paper exact analytical solutions of uniform flow depth for rectangular and trapezoidal section have been obtained in the form of fast converging power series.

New Solution of Classical Hydraulic Jump

2009

This technical note, applying dimensional analysis and incomplete self-similarity, proposes a new functional relationship for the sequent depth ratio for hydraulic jumps over both smooth and rough horizontal beds. For the smooth bed condition, experimental measurements in the literature were used to calibrate the new relationship. For the rough bed condition the data of a previous investigation were used with new measurements carried out in a rectangular horizontal flume having a gravel bed. Finally, a generalized solution of the sequent depth ratio is proposed.

A three-dimensional study of the onset of convection in a horizontal, rectangular porous channel heated from below

2012

Author's version of an article published in the journal: International Journal of Thermal Sciences. Also available from the publisher at: http://dx.doi.org/10.1016/j.ijthermalsci.2011.12.012 The onset of convection is studied in a rectangular channel filled with a fluid saturated porous medium, bounded above and below by impermeable isothermal walls at unequal temperatures and laterally by partially conducting walls. A three-dimensional linear stability analysis is carried out under the assumption of an infinite longitudinal channel length. Then, this assumption is relaxed in order to determine the threshold length for the three-dimensional convection to be the preferred mode at onset. Sens…

Hydraulic jumps on rough beds

2007

This paper presents the results of an experimental investigation on the hydraulic jump on horizontal rough beds. Experiments were carried out to study the effect of bed roughness on both the sequent depth ratio and the roller length. The investigation allowed the writers to positively test the reliability of a new solution of the momentum equation for the sequent depth ratio as a function of the Froude number and the ratio between the roughness height and the upstream supercritical flow depth. The applicability of some empirical relationships for estimating the roller length was also tested.