S.Mohamad Sadegh Rasooli; Amirhossein Bazaee; Roozbeh Aghamajidi
Abstract
Affected by numerous elements, the estimation of manning's roughness coefficient is of great importance and sensitivity. In the present study a reach of 56 km from beshar river in kohgiluyeh and boyer-ahmad province was studied. The selected reach was divided into 12 sub-reaches based on similar characteristics. ...
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Affected by numerous elements, the estimation of manning's roughness coefficient is of great importance and sensitivity. In the present study a reach of 56 km from beshar river in kohgiluyeh and boyer-ahmad province was studied. The selected reach was divided into 12 sub-reaches based on similar characteristics. Experimental and quasi-experimental methods, tables, and cowan's method were used to estimate manning's coefficient. The estimation results were compared with stage-discharge rating curves from two hydrometric stations located in the selected reach. The ‘inverse solution’ was proved to be the best method to estimate manning's coefficient in the river under study followed by bruschin and cowan's method with an average error of 0.237 and 0.241, respectively.
Rahim Hajibagheri; Amirhossein Bazaee; Roozbeh Aghamajidi
Abstract
The phenomenon of flood, in spite of all its complexities, can be studied and appropriate solutions can be sought to control and reduce its damage and even economic exploitation of floods. On the other hand, before constructing any hydraulic structure such as dams, overflows, diversion channels, temporary ...
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The phenomenon of flood, in spite of all its complexities, can be studied and appropriate solutions can be sought to control and reduce its damage and even economic exploitation of floods. On the other hand, before constructing any hydraulic structure such as dams, overflows, diversion channels, temporary dams, etc., it is necessary to have the information of maximum possible flood and flood hydrograph with different return periods in order to estimate the magnitude of different floods and predicted the maximum height of the river flood zone, the maximum area and width of the river flood in different areas, the maximum flow velocity, changes in shear stress, flood volume, changes in landing number and hydraulic radius, etc. flood routing and zoning operations or quantifying river confluence for flood alert systems. in this study, by selecting the case of Sivand river in fars province in the specified time period, flood frequency analysis was performed with the help of Smada and Easyfitt software and the maximum flood discharge was determined with different return periods. then, by selecting tangbolaghi hydrometric station as the representative station of Sivand river, hydraulic flood routing and zoning operations were attempted by Mike11 computer model.
Saeed Radmanesh; Amirhossein Bazaee; Roozbeh Aghamajidi
Abstract
Overflows are generally installed to drain excess water or floods that the volume of the tank can not store. In diversion dams, overflow is used to bypass or divert current in excess of system capacity. Demolition of many dams occurs due to incorrect design or insufficient overflow capacity. Proper spill ...
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Overflows are generally installed to drain excess water or floods that the volume of the tank can not store. In diversion dams, overflow is used to bypass or divert current in excess of system capacity. Demolition of many dams occurs due to incorrect design or insufficient overflow capacity. Proper spill design is more important in gravel earthen dams than in concrete dams. because the probability of destruction of earthen and gravel dams due to water passage is much higher than concrete dams. In the present study, a comprehensive review of the types of applied overflows based on effective dynamic and kinematic parameters was performed. Also, definitions and summaries of different types of free overflows were shot, siphon, stepped, congressional, lateral, tunnel, circular crown, peak, lotus or tulip. Then, the mechanism of vortex formation was introduced and an overflow appropriate to this phenomenon was introduced. The results of these cases showed that the application of lotus or tulip overflow in flood areas with high discharge has better performance.
Saeed Radmanesh; Amirhossein Bazaee; Roozbeh Aghamajidi
Abstract
In general, Spillway are divided into two types linear and non-linear, among which, the Morning Glory overflow is a non-linear overflow. In some cases, the hydraulic performance of the overflow is affected by the immersion coefficient and its hydraulic efficiency is reduced and affected by the immersion. ...
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In general, Spillway are divided into two types linear and non-linear, among which, the Morning Glory overflow is a non-linear overflow. In some cases, the hydraulic performance of the overflow is affected by the immersion coefficient and its hydraulic efficiency is reduced and affected by the immersion. Structures such as vortex breakers (separators of flow lines to increase transit efficiency) and to increase overflow efficiency should be used. In this regard, using dimensional analysis by Buckingham method, it was determined that the overflow coefficient of the overflow is a function of variables such as vortex breaker height ratio (Hvb / Rs), vortex breaker thickness ratio (Tvb / Rs), number of vortex breakers (VB) and overflow shape factor ( Sf) is. The experiments of the present study were performed on a square flume with dimensions of 2.5 × 2.5 and a height of 2 m 0.20 1 1.05 /0 1.05 m3. The results showed that the overflow of stepped Morning Glory (12 steps) and vortex breaker with high height and 6-array arrangement has a much better and more suitable performance compared to non-stepped overflow and has increased the permeability coefficient by 23%.
