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Thursday, 17 March 2011 16:48

SPECIFICATION OF SEDIMENT-CARRYING CAPACITY BY STREAM BASED ON THEORY OF DIMENSIONS

P.BALDJAN,  O.KELEDJAN
 (Armenia)

Analysis of calculation methods of sediment-carrying capacity by stream allowed the authors to determine basic parameters conditioning the sediment-carrying capacity by the stream S or the sediment discharge value Qt.

The value of the motion of the sediment-capacity of the mountain rivers is less determined today. Based on the research analysis of the field and in-situ observations, the issues of flow, drift and bed parameters determining the sediment discharge value are worked out. Using the theory of dimensions, criterion equation for specifying the sediment-carrying capacity by the stream is obtained.



FORECASTING POSSIBLE ECOLOGICAL STRESSES IN RIVER ESTUARIES AS A RESULT OF ACCIDENTS AT MAIN OIL PIPELINES

D.NAMGALADZE, I.LOMIDZE, L.SHATAKISHVILI
(Georgia)

Issues of forecasting possible ecological stresses in river estuaries as a result of accidents at the main oil pipelines particularly, identification of the trajectory of oil jet flowed into the estuary are reviewed. Linear idealization of the velocity distribution in the river is used at the first stage of identifying the trajectory of the oil jet flowed into the estuary which is a one-branch river mouth expanding towards the sea. In this case, the jet trajectory has a very complicated shape, initially it runs down and then, when it reaches the point, where the flow changes its direction, the radius of the jet curve changes. The jet makes loop and just after this comes up to the flow surface. Mathematic program, Maple 95 does not provide an evident mathematic solution since the presence of the jet loop creates certain uncertainties. In order to avoid such difficulties, a modified sub-program of Maple 95 will be written according to which the calculation of the jet coordinates is run by areas. In particular, the program terminates the calculation and initiates recalculations as soon as the jet trajectory changes its direction. The difference between the results obtained and the in-situ data does not exceed 15-20%. Thus, it is evident that the method suggested for preliminary engineering evaluation is quite acceptable.



RESEARCH OF NONSTATIONARY PLANE-PARALLEL PRESSURE FLOW OF VISCOUS LIQUID UNDER FIXED DIFFERENTIAL PRESSURE

A.SARUKHANYAN, A.MARKARYAN, A.MANUKYAN
(Armenia)

Nonstationary plane-parallel pressure flow of viscous liquid under the conditions of fixed differential pressure is reviewed.

Regularities of nonstationary hydromechanic parameter change of the plane-parallel pressure flow for the presence of fixed differential pressure are obtained. These regularities under the presence of fixed differential pressure allow to determine the character of ongoing processes.

It is obvious from the obtained diagrams that in low Reynolds number, transient process strives for the stationary mode, and in their large numbers – nonstationary mode maintains its condition for a long time.



ANALYTICAL DETERMINATION OF WASHING TIME OF HEAD WATER OF WATER RECEIVING STRUCTURE

L.TOKMAJAN, P.BALDJAN, A.MARKARYAN
(Armenia)

Head water of water receiving structures located in the mountain rivers is often sandy. Therefore, large amount of sand and gravel runs into the canals causing the emergency situation. Based on mathematical modeling of washing process, the determination of intermediate and full washing time of the head water of the water receiving is developed. With this, it is possible to effectively plan the operational conditions of the hydrosystem.

Common charts of the head water washing as well as profile and scheduled charts are given on figures.

Practical recommendations for applying the method suggested by the author are presented.

Last Updated on Friday, 18 March 2011 13:38
 
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