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Investigation of turbulence characteristics in channel with dense vegetation

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International Journal of Sediment Research 2011年第3期26卷 269-280+282+281页

作者： Hossein AFZALIMEHR Razieh MOGHBEL jacques gallichand Water Engineering Department Isfahan University of TechnologyIran 84156 Departement des sols et de genie agroalimentaire Universite LavalSt-FoyQcCanada

In this experimental study,the turbulent flow in a channel with vegetation by using sprouts of wheat on channel bed was *** different aspect ratios of channel were *** Acoustic Doppler Velocimetry was used to measure parameters of turbulent flow over submerged sprouts of wheat,such as velocity *** log law and the Reynolds shear stress distribution were applied. Results indicate that the position of the maximum turbulence intensity superposes on the inflection point situated over the top of submerged vegetation *** analysis shows that near the vegetation bed,the sweeps and ejections appear to be the most dominant phenomenon,while far from the vegetated bed,the outward is dominant *** also show that the aspect ratio plays an important role on the contribution of the different bursting events for Reynolds stress determination.

关键词： Bed vegetation Aspect ratio Reynolds stress Quadrant analysis

Field investigation on friction factor in mountainous cobble-bed and boulder-bed rivers

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International Journal of Sediment Research 2011年第2期26卷 210-221页

作者： Hossein AFZALIMEHR jacques gallichand Ehsan BAGHERI Department of Water Engineering Isfahan University of Technology Departement des sols et de genie agroalimentaire Universite Laval Water Engineering Department Isfahan University of Technology

This paper presents results of the friction factor of cobble-bed and boulder-bed rivers based on 23 field measurements in three mountainous rivers in *** reveal that features of our measured velocity profiles in boulder-bed rivers in mountainous region do not present a specific shape but illustrate specific pattern in cobble-bed *** difference is attributed to scale effect of relative submergence. It is found that the relative submergence in cobble and boulders-bed rivers is the only key parameter that influences friction factor estimation and other parameters such as particle Froude number and Froude number have few impacts on flow resistance of cobble-bed and boulder-bed *** proposed relationship for estimation for the friction factor should be useful for large coarse-bed rivers.

关键词： Boulder-bed Cobble-bed Friction factor Mountainous river Relative submergence

Effects of accelerating and decelerating flows in a channel with vegetated banks and gravel bed

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International Journal of Sediment Research 2012年第2期27卷 188-200页

作者： Hossein AFZALIMEHR Elham Fazel NAJAFABADI jacques gallichand Department of Water Engineering Isfahan University of Technology84156-83111Iran Dpartement des sols et de gnie agroalimentaire Pavilion Paul-Comtois Universit LavalSt-FoyQCCanada

Experiments were conducted in an 8 m long,40 cm wide,and 60 cm deep re-circulating flume with vegetated banks and gravel bed to study the effects of accelerating and decelerating flows on the flow *** dip phenomenon was observed in velocity profiles under decelerating flow and the velocity defect law was not suitable due to the effect of vegetated *** the vegetated banks, the turbulence intensities illustrated convex distribution for both accelerating and decelerating flows. Application of quadrant analysis revealed that the effect of vegetated banks is important on the flow structure and the Reynolds stress *** and decelerating flows did not show a significant difference on percentage of time occupied by each kind of turbulent event within bursting cycle,but affected the shape of joint probability distributions of turbulent intensities in the horizontal and vertical directions.

关键词： Vegetated bank Decelerating and accelerating flows Gravel bed Reynolds stress

Influence of Sludge Incineration Ash on Ryegrass Growth and Soil Phosphorus Status

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Pedosphere 2019年第1期29卷 70-81页

作者： Claude-Alla JOSEPH Lotfi KHIARI jacques gallichand Marc HBERT Ned BEECHER Department of Soil Science and Agrifood Engineering Laval University Ministry of Sustainable Development Environment and the Fight Against Climate Change (MDDELCC) North East Biosolids & Residuals Association (NEBRA)

Phosphorus(P) is a limited resource that could be depleted. Consequently, recycling the P contained in sewage sludge, including sewage sludge incineration ash(SIA), from wastewater treatment plants is a possibility to be explored. A greenhouse experiment using annual ryegrass(Lolium multiflorum L.) was performed with an experimental design of three completely randomized blocks of two soils and 29 treatments: one control without P and two levels of 9 and 26 kg total P ha^(-1) from 14 different sources: twelve SIAs(not contaminated by trace metals) from the US and Canada, one commercial synthetic fertilizer(triple superphosphate(TSP)), and one commercial rock phosphate(RP). Higher ryegrass biomass levels were achieved at the higher fertilization rate(26 kg total P ha^(-1))and when using the SIAs with the highest P solubility percentage(PSP)(≥ 54% of total P). The biomass increases following SIA application were as high as 29% and 59% more than the control for the sandy loam and clayey soil, respectively, but 40% less than in TSP for both soils. A similar behavior was observed for P uptake, with a maximum increase of 26% for the clayey soil, and 165% for the sandy loam soil. The ryegrass biomass and P uptake increases due to SIA application were larger than those due to RP application in the clayey soil, but similar to those in the sandy loam soil. The SIAs with a PSP of ≥ 54% significantly increased soil available P stocks and saturation. According to our findings, we conclude that the SIAs from municipal and agrifood industries have a potential for P agricultural recycling, but their efficiencies vary.

关键词： biomass P recycling P solubility percentage P uptake rock phosphate triple superphosphate

维普期刊数据库

Optimizing the dataset size of a topo-bathymetric survey for Hammam Debagh Dam, Algeria

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International Journal of Sediment Research 2018年第4期33卷 518-524页

作者： Djamel Bengora Lotfi Khiari jacques gallichand Noureddine Dechemi Silvio José Gumiere Department of Hydraulics Polytechnic National School Department of Soil and Agrifood Engineering Laval University

The capacity of water reservoirs may be considerably reduced by sediment transport and *** phenomenon may occur quickly in regions prone to erosion, such as Hammam Debagh Dam region in Algeria. For better management of water resources, it is important to estimate the volume of a reservoir by regular and frequent topo-bathymetric surveys. Topo-bathymetric surveys with a high point measurement density are expensive and time-consuming. To reduce this expense and to increase the frequency of topo-bathymetric surveys, it is required to optimize their size and density. The complete survey of the reservoir created by the Hammam Debagh Dam in Algeria was examined in comparison with 19 reduction subsets using geostatistics. The study showed that the complete dataset of 32,164 points, corresponding to a density of 42 points ha-1could be reduced to 10,000 points, i.e. 13 points ha-1,without affecting the estimation of the water volume in the reservoir. This reduction could considerably simplify the work load, reduce the expenses to do these surveys, and, therefore, allow for an increased frequency of topo-bathymetric surveys.

关键词： Dam Reservoir Silting Volume estimation Point measurement density Volume/elevation curve

Positioning Temperature Sensors for Frost Protection in Northern Cranberry Production

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Agricultural Sciences 2017年第9期8卷 960-971页

作者： Vincent Pelletier Silvio Jose Gumiere Steeve Pepin jacques gallichand Jean Caron Département des Sols et de Génie Agroalimentaire Université Laval Québec Canada

Frost can cause serious economic losses in cranberry fields, particularly in northern regions. When the air temperature reaches a low critical threshold, sprinklers are operated to protect vines, to insure crop production and profitability. To avoid frost injury, proper positioning of temperature sensors is critical. A field experiment was designed and conducted to determine the optimal installation height of sensors above soil surface. Temperature data was used to investigate the spatial temperature gradient in the section of a cranberry field. A computer simulation of the temperature profile was performed to simulate the effect of wind velocity on the prediction of air temperature. For optimal use, sensors should be installed at the height of the canopy and several meters away from a dike. On nights with low wind velocities, the canopy air temperature was 2.7°C below that of 500 cm above the ground. The sensors should be put at least five m away from a dike to avoid the transfer of heat from the dike to the sensor. Also, multiple sensors should be installed because of the large variations in air temperature that were measured across the experiment. The simulated temperature indicated that wind velocity strongly influenced the temperature estimation;the effect of the wind on temperatures gradients was greater when the wind velocity was low (<2.3 m/s).

关键词： Frost Protection Cranberry Production Numerical Simulation of Heat Transfer