Modeling of Wave Phenomena on the Shallow Water Surface

2018 ◽  
pp. 23-64
Keyword(s):  
Shallow Water ◽  
Water Surface ◽  
Wave Phenomena

scholarly journals Performance Study of a Floricultural Greenhouse Surrounded by Shallow Water Ponds

2017 ◽  
Vol 6 (2) ◽  
pp. 137
Author(s):  
Debajit Misra ◽  
Sudip Ghosh
Keyword(s):  
Shallow Water ◽  
Water Surface ◽  
Natural Ventilation ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Free Water ◽  
Weather Data ◽  
Ventilation Mode ◽  
Performance Study ◽  
Tropical Regions

In the present paper, an innovative low energy-intensive evaporative cooling system has been proposed for greenhouse application in near-tropical regions dominated by hot climate. The system can operate under dual- ventilation mode to maintain a favourable microclimate inside the greenhouse. A single ridge type un-even span greenhouse has been considered, targeting a few species of Indian tropical flowers. The greenhouse has a continuous roof vent as well as adjustable side vents and is equipped with exhaust fans on top and roll-up curtains on the sides. The greenhouse is surrounded by shallow water ponds outside its longitudinal walls and evaporative surfaces partially cover the free water surface. Inside the pond, low cost evaporative surfaces are so placed that they form air channels.  Thus, outside air flows through the channels formed by the wetted surfaces over the water surface and undergoes evaporative cooling before entering the greenhouse. A simplified theoretical model has been presented in this paper to predict the inside greenhouse air temperature while ambient weather data are used as model inputs. The study reveals that during average radiation periods, the greenhouse can depends solely on natural ventilation and during peak radiation hours fan-induced ventilation is needed to maintain the required level of temperature. It is seen that under dual-ventilation mode greenhouse, temperature can be kept 3-6 oC lower than ambient temperature when saturation effectiveness is 0.7 and with 75% shading. Keywords: Greenhouse, Evaporative Cooling, Ventilation, Saturation Effectiveness, Wetted SurfaceArticle History: Received February 25th 2017; Received in revised form April 14th 2017; Accepted May 4th 2017; Available onlineHow to Cite This Article: Misra, D. and Ghosh, S., (2017) Performance Study of a Floricultural Greenhouse Surrounded by Shallow Water Ponds. International Journal of Renewable Energy Develeopment, 6(2), 137-144.https://doi.org/10.14710/ijred.6.2.137-144

Cuspon-type Waves and Their Properties

2021 ◽  
Vol 24 (2) ◽  
pp. 145-155
Author(s):  
G. Omel’yanov
Keyword(s):  
Shallow Water ◽  
Traveling Waves ◽  
Water Surface ◽  
First Derivative ◽  
Shallow Water Approximation

The general Degasperis-Prosesi equation (gDP) describes the evolution of the water surface in a unidirectional shallow water approximation. We consider essentially non-integrable versions of this model and analyze their cuspon-type solutions, that is continuous traveling waves with the unbounded first derivative.

scholarly journals Shallow Water Measurements Using a Single Green Laser Corrected by Building a Near Water Surface Penetration Model

2017 ◽  
Vol 9 (5) ◽  
pp. 426 ◽  
Author(s):  
Jianhu Zhao ◽  
Xinglei Zhao ◽  
Hongmei Zhang ◽  
Fengnian Zhou
Keyword(s):  
Shallow Water ◽  
Water Surface ◽  
Green Laser

1D flow simulation with irregular cross-sections using the pre-balanced shallow water equations

2020 ◽  
Author(s):  
Shangzhi Chen ◽  
Feifei Zheng ◽  
Qingzhou Zhang
Keyword(s):  
Shallow Water ◽  
Cross Sections ◽  
Shallow Water Equations ◽  
Water Surface ◽  
Numerical Scheme ◽  
River Flow ◽  
Source Term ◽  
Complex Topography ◽  
Wetting And Drying ◽  
Prismatic Channel

<p>With the possible climate change and increased pace of urbanization in the century, urban flooding has caused more and more attentions nowadays. Shallow water equations are widely used to reproduce the flow hydrodynamics of flooding around the urban areas, which have been proved a powerful tool for flood risk assessment and evacuation management, like river flow or flowing at drainage networks with irregular cross-sections at 1D scale. Over the last two decades, Godunov-type schemes have became popular for its robustness treating complex flow phenomenons. When tacking complex topography in the framework of Godunov-type scheme, sourer term needs to be treated property to preserve steady state, that flux gradient and sourer term are balanced. Capart et al. (2003) reconstructed the momentum flux by considering the balance of hydrostatic pressure with the approximated water surface level, which has the ability to tackle the irregular and non-prismatic channel flow with complex topography. This approximation is exact for two cases: 1) rectangular and prismatic channel; 2) water surface is horizontal. However, for other cases, approximation is employed to achieve the hydrostatic equilibrium, which has reduced the accuracy of the numerical solution and increased the complexity for the model implementation. </p><p>In this work, we present a new well-balanced numerical scheme for simulating 1D frictional shallow water flow with irregular cross-sections over complex topography involving wetting and drying. The proposed scheme solves, in a finite volume Godunov-type framework, a set of pre-balanced shallow water equations derived by considering pressure balancing (Liang and Marche, 2009). HLL approximated Riemann solver is adopted for the flux calculation at the cell interface. Non-negative reconstruction of Riemann state (Audusse et al., 2004) and local bed modification (Liang, 2010) produce stable and well-balanced solutions to shallow water flow hydrodynamics. Bed slope source term can be approximated using central difference and no special treatment is needed for wet and dry bed. The friction source term is discretized using a splitting implicit scheme and limiting value of friction force is used to ensure stability for the dry bottom (Liang and Marche, 2009). The new numerical scheme is validated against two theoretical benchmark tests and then compared with the validated shallow water model with circular and trapezoid cross-sections over complex topography involving wetting and drying. This method is also possible to reproduce the mixed flow in the conduit or for the flow with non-prismatic channel like river flow in the near future.</p><p>References</p><p>Audusse, E., Bouchut, F., Bristeau, M. O., Klein, R., & Perthame, B. T. (2004). A fast and stable well-balanced scheme with hydrostatic reconstruction for shallow water flows. SIAM Journal on Scientific Computing, 25(6), 2050-2065.</p><p>Capart, H, Eldho, TI, Huang, SY, Young, DL, and Zech, Yves, "Treatment of natural geometry in finite volume river flow computations", Journal of Hydraulic Engineering 129, 5 (2003), pp. 385--393.</p><p>Liang, Qiuhua and Marche, Fabien, "Numerical resolution of well-balanced shallow water equations with complex source terms", Advances in water resources 32, 6 (2009), pp. 873--884.</p><p>Liang, Qiuhua, "Flood simulation using a well-balanced shallow flow model", Journal of hydraulic engineering 136, 9 (2010), pp. 669--675.</p>

scholarly journals A new method for measuring fish swimming patterns in shallow water and a previously undescribed swimming gait

2019 ◽  
Author(s):  
Jay Willis ◽  
Theresa Burt de Perera ◽  
Guillaume Poncelet ◽  
Adrian Thomas
Keyword(s):  
Shallow Water ◽  
Water Surface ◽  
Close Contact ◽  
Low Cost ◽  
Amphibian Larvae ◽  
Swimming Mode ◽  
New Type ◽  
Set Up ◽  
Fast Flow ◽  
Rheophilic Fish

AbstractHill stream loaches are fish which live their entire lives in close contact with rock. They have elaborate physical adaptations to fast flow, adherence to substrate, and movement in very shallow water. Here we describe a method for observing how they swim in detail. There are many similarly shaped rheophilic fish, insects, and amphibian larvae, which live in fast flowing water, and a method of observing their swimming modes has wide potential application. We measured the deflection of the water surface around a swimming fish by viewing a fixed pattern on the bottom of the tank through the water surface. This is a Schlieren method in which the movement or other physical properties of a medium are derived from the deflection of a pattern viewed through that medium. We used this method to describe a new type of swimming gait which is likely to be common among small rheophiles – pulse swimming mode – in which thrust is produced in a series of discrete impulses. The method of analysis described here is beneficial in that the fish is allowed to swim freely in relatively normal conditions without the use of intrusive equipment such as lasers, dyes, or additives to the water, and the pattern of thrust is viewed directly against the skin of the fish rather than being inferred from the wake pattern behind the fish. The method is also low cost and easily set up.

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