scholarly journals Modeling of weir height drop on the slope of the open channel hydraulic jump

2020 ◽  
Vol 1 (1) ◽  
pp. 011-026
Author(s):  
Jerome Godwin Egbe ◽  
Jonah Chukwuemeka Agunwamba
Keyword(s):  
Hydraulic Jump ◽  
Open Channel ◽  
Research Centre ◽  
Model Design ◽  
Research Facility ◽  
Response Variable ◽  
Direct Model ◽  
Weir Height ◽  
Height Drop ◽  
Pressure Driven

The model design was developed for the alignment and it was utilized to test for various geometrics and stream conditions searching for a low and incentive for RMSE and the response variable. Also, during the alignment half of the exploratory information was set to their coefficients, and the staying set of information was similarly be utilized for confirmation purposes. Utilizing around thirty out of the fifty informational collections created in the research facility dependent on relapse investigation was applied to the non-direct model to decide the constants. The staying twenty informational collections from research centre analyses were utilized for check of the model. The absence of the fittest was utilized likewise to check the request for the proposed relapse model utilizing the water profundity as the response variable. The Froude numbers from the post-pressure driven hop segment from 0.37 to 0.41 (0.37 < Fr3< 0.41), likewise showing that the streams are subcritical. The Froude numbers from the post-pressure driven hop area inside 0.37 to 0.41 (0.37<Fr3 <0.41), this shows the streams are subcritical. The connection between sequent profundity proportion y3//y2 and speed proportion V2/V3 is around - 5024 +1.485 Fr2 with R2 =0.9957 showing that as the sequent profundity proportion and speed proportion expands the inflow Froude number Fr2 additionally increments, the hydraulic jump extended from - 0.001 to 0.001 which gives some vitality progression with an expansion in the pace of release through the flume. The upstream of the flume, the Froude numbers go from 0.038 to 0.052 (0.038 < Fr1 < 0.52), demonstrating that the streams were subcritical and less harm to the channel.

Water budget and subsurface runoff determination for small Alpine catchments using WaSIM

2021 ◽  
Author(s):  
Daniel Bergmeister ◽  
Klaus Klebinder ◽  
Bernhard Kohl ◽  
Ulrich Burger ◽  
Georg Orsi ◽  
...  
Keyword(s):  
Water Balance ◽  
Water Budget ◽  
Meteorological Data ◽  
Modular System ◽  
Research Centre ◽  
Main Study ◽  
Direct Model ◽  
Subsurface Runoff ◽  
Alpine Catchments ◽  
Brenner Base Tunnel

&lt;p&gt;Assessing the water balance including subsurface runoff in high Alpine catchments is still a major challenge due to environmental and meteorological complexity, and mostly data-lacking hydrology. The aim of this study is the determination of the water balance components and water budget with focus on approximation of interflow, subsurface runoff and groundwater interactions, depending on sediment and bedrock properties.&lt;/p&gt;&lt;p&gt;In this process we investigate a small, high data providing Alpine catchment in the Wipp Valley (Tyrol, AT) to evaluate the best modelling approach in order to apply it on catchments along the Austrian Brenner axis. Thus, a direct model comparison of the main study catchment, with its (moderate data providing) neighbouring valley is carried out. The main study catchment (Padaster Valley) covers 11.2 km&lt;sup&gt;2&lt;/sup&gt; and is located east of Steinach am Brenner in the Wipp Valley. Due to its partially usage as a deposital site, respectively a landfill for the tunnel excavation material of the Brenner Base Tunnel, this valley represents a highly interesting site in a hydrological aspect. Thus, the Padaster Valley is highly monitored and hence predestined for hydrological investigations. Hydrological data such as discharge is measured high frequently on four gauges, meteorological data on two gauges. An additional study catchment (Navis Valley) covers 63 km&lt;sup&gt;2&lt;/sup&gt; and is located northerly next the Padaster Valley. Seven gauges provide meteorological data, however, continuous discharge data is just measured at the valley mouth. Further meteorological data for both areas will be contributed by the ZAMG (Zentralanstalt f&amp;#252;r Meteorologie und Geodynamik), whose INCA model provide a high spatial resolution dataset of 1km. However, in order to gain a better overall understanding of subsurface runoff and hydrogeological processes, geological data will be considered and incorporated/integrated in the modelling process. This includes geological maps, - cross sections and geophysical analysis, which help to estimate the bedrock topography, and consequently the volume as well as deeper seated hydrogeological properties of the sediment cover. In this context, continuous data from 7 groundwater observation wells provide information regarding groundwater levels and hydraulic head. To increase the model accuracy regarding subsurface flow processes, subsurface-depending runoff types after Pirkl &amp; Sausgruber (2015) are applied. Furthermore, several maps such as land use, surface runoff coefficient and soil map including grain size distribution of the layers have been compiled by in-situ fieldwork for this study. In order to model the water budget, subsurface runoff and overall hydrological slope properties, the distributed hydrological Model WaSIM (Richards version; Schulla, 1997) is applied. The model is based on a modular system which uses physically-based algorithms.&lt;/p&gt;&lt;p&gt;The present study is been carried out by the Austrian Research Centre for Forests (BFW) in collaboration with the Brenner Base Tunnel (BBT-SE).&lt;/p&gt;

scholarly journals Apron and Cutoff Wall Scour Protection for Piano Key Weirs

Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2332
Author(s):  
Wyatt Lantz ◽  
Brian Mark Crookston ◽  
Michele Palermo
Keyword(s):  
Large Scale ◽  
Open Channel ◽  
Control Structure ◽  
Cutoff Wall ◽  
Specific Design ◽  
Experimental Campaign ◽  
Hydraulic Conditions ◽  
Weir Height ◽  
Scour Protection ◽  
Design Guidance

Piano key (PK) weirs are used in a variety of flow control structure applications, including spillway crests and open channel diversion structures. However, to the best of authors’ knowledge, structure-specific design guidance for scour mitigation is still needed. To fill this gap of knowledge, a systematic experimental campaign was conducted by testing different configurations of horizontal aprons with a cutoff wall. Protection structures were located at the toe of the PK weir. Namely, experiments were performed at large-scale to assess the effect of three apron lengths on downstream scour hole geometry under different hydraulic conditions. It was observed that a horizontal apron deflects the plunging jets originating from the PK weir, thus significantly reducing scour. Experimental evidence allowed corroboration that significant scour depth reduction occurs for an apron length 1.5 times the weir height, with longer aprons found to provide marginal benefits. Finally, also provided herein are tools to estimate the main scour characteristics and help practitioners in optimizing apron design.

Classical hydraulic jump: free surface profile

1993 ◽  
Vol 20 (3) ◽  
pp. 536-539 ◽  
Author(s):  
Willi H. Hager
Keyword(s):  
Free Surface ◽  
Channel Flow ◽  
Hydraulic Jump ◽  
Simple Formula ◽  
Open Channel ◽  
Surface Profile ◽  
Novel Approach ◽  
Flow Hydraulics ◽  
Channel Surface ◽  
Free Surface Profile

Based on a large number of experiments, a simple formula is developed for the time-averaged free surface profile of a classical hydraulic jump. This novel approach is based on the length of the roller. The resulting surface profile fits the data well for usual inflow Froude numbers in the range of 2 to 10. Key words: backwater, channel flow, hydraulics, open channel, surface profile.

The undular hydraulic jump in turbulent open channel flow at large Reynolds numbers

2003 ◽  
Vol 15 (3) ◽  
pp. 730-735 ◽  
Author(s):  
Wolfgang Grillhofer ◽  
Wilhelm Schneider
Keyword(s):  
Channel Flow ◽  
Hydraulic Jump ◽  
Open Channel ◽  
Open Channel Flow ◽  
Reynolds Numbers

On the Hydraulics of Downward Sloping Pipes With Entrapped Air Pockets

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
H. A. Warda ◽  
E. M. Wahba ◽  
E. N. Ahmed
Keyword(s):  
Hydraulic Jump ◽  
Open Channel ◽  
Numerical Results ◽  
Navier Stokes ◽  
Experimental Investigations ◽  
Dynamics Model ◽  
Computational Fluid Dynamics Model ◽  
Air Pocket ◽  
Entrapped Air ◽  
Air Pockets

Abstract In this study, air–water flow in a downward sloping pipe subsequent to the entrapping of an air pocket is investigated both numerically and experimentally. A transient, two-dimensional computational fluid dynamics model is applied to study the different possible flow regimes and their associated phenomena. The numerical model is based on the Reynolds-averaged Navier–Stokes (RANS) equations and the volume of fluid (VOF) method. Both numerical and experimental investigations provide visualization for the hydraulic jump, the blowback regime, and the full gas transport regime. The numerical results predict that the flow structure in the pipe downstream the toe of the hydraulic jump is subdivided into three distinct regions including the jet layer, the shear zone, and the circulation region, which agrees qualitatively with the previous investigations of the hydraulic jump characteristics in open channel flow. Numerical results are in reasonable agreement with the experimental measurements of the circulation length and the hydraulic jump head loss.

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