Applied Mechanics and Materials Vols. 353-356

Abstract: Through analysis of the annual rainfall data from 1918 to 2005 in Tianjin, wet-dry year was determined; the abundant and low state of annual rainfall series and its durative in Meijiang lake region was studied. The results show that the occurrence of the dry year is most probable; the durative probabilities in descending order are: low, abundant and normal state; there is the highest probability of transition from low to low state, which indicates a more probable occurrence of large amount of water diversion.

Abstract: The traditional dam seepage monitoring model is based on the relationship of seepage elements with the upstream reservoir water level and rainfall, which includes the impact of base value, this model will weaken the effects of reservoir water level variation and rainfall on the variation of seepage elements, especially under the condition of high reservoir water level and smaller head fluctuation, so components separated by this model are not normally the practical. Based on the theory of unsteady seepage, the lag effect function has been introduced into the seepage monitoring model to take the lag effect of reservoir water level variation and rainfall into account, and the daily variation monitoring model of dam seepage elements is established. Case studies are in good agreement with original observations, so the proposed model can be used in the daily variation monitoring and forecasting of dam seepage elements.

Abstract: The paper made a comprehensive introduction in model tests of the desilting tunnel of Longkou hydropower station, including prototype information, experimental purposes and content, then doing the comparative analysis of the theoretical calculations and data that observing by instruments. The tests results show that it is reasonable that desilting tunnel overall layout and the design type of the desilting tunnel, the various hydraulic elements that under various hydraulic conditions and the flow pattern of upstream and downstream have no serious adverse effects on desilting tunnel itself and other buildings, it play a role of support and verification to the design program.

Abstract: The simple and efficient facilities of steady flow and wave elimination-flow-stabilizing plate and wave-eliminating barrier were introduced to study strong water surface fluctuation existing in free flow tunnel in Aan water project, through comparative trial and fluctuation analysis, it could be found that the introduction of steady-flow and wave-elimination facilities could stabilize the flow pattern of free flow tunnel.

Abstract: Lagrangian and Eulerian modelling approaches are compared for simulating turbulent dispersion and coalescence of droplets within a spray. Both models predict similar droplet dispersion rates and shifts in droplet size distribution due to coalescence within the spray, over a wide range of droplet and gas flows, and for sprays with different droplet size distributions at the nozzle exit. The computer time required for simulating coalescence within a steady axisymmetric spray is of a similar order of magnitude regardless of which formulation, Eulerian or Lagrangian, is adopted. However, the Lagrangian formulation is more practical in terms of the range of applicability and ease of implementation.

Abstract: To overcome the deficiency that model experiments are unable to take accurate measurements without damaging the structure of the fine flow fields, a large eddy simulation is employed to simulate the three dimensional structure of the flow passed a pervious cubic-blunt body at Re=2.2×10⁴. A comparative analysis have been taken qualitatively and quantitatively between the flow passed a pervious cubic-blunt body and the flow passed a non-pervious cubic-blunt body from the aspects of the flow structure (mainly including separation and reattachment), unsteady vortex shedding, distribution of static pressure and drag coefficient, etc. Therefore, characteristics of this kind of flow field are concluded and along with a better understanding of concrete effects they bring, which can give guidance to engineering.

Abstract: This Base on the the field data of water and sediment of Yangtze River estuary bifurcation in 2004 fiood season and 2005 dry season, the features and process of water and sediment transport Was analyzed by decomposition mechanism.The law of velocity of residual currentsediment transport rate per unit width and tidal punping effect,which in different season and tide,are focused on.The relationship between the features of water and sediment and channel wvolution was discussed through the results of the discharge of water and sediment,which is a basis in the future study of discharge of water and sediment in estuary.

Abstract: Combined with a multi-level intake structure, using the standard two-equation turbulence model to carry on the three-dimensional numerical simulation for the hydraulic characteristics of this intake .The flow velocity, fluid flow distribution and head loss were analyzed and summarized. The vertical velocity distribution near the intake has been significantly changed after placed stop log gate, the flow velocity of the reservoir surface water near the intake increases significantly, more surface water enter the power plant unit, and the head loss increases greatly.

Abstract: Reservoir warning is an important part of the red line of water resources development control. Based on the red line of total water in three red lines, this paper put forward firstly the quantitative method for determining water supply line and warning area of irrigation reservoirs, and presented the definition and method of irrigation reservoir warning. Taking the Douyazi reservoir in Jiaonan for example, early warning results based on warning period, which was divided into three months and non-flood season, were given. It provided technical support for implementation of the most strict resources management and sustainable development of the economic society.

Abstract: A three dimensional non-hydrostatic numerical model is presented based on the incompressible Navier-Stokes equations and mass transport equations. An unstructured finite-volume technique is used to discretized the governing equations with good adaptable to complicated boundary. A conservative scalar transport algorithm is also applied in this model. An integral method of the top- layer pressure is applied to reduce the number of vertical layers. Three classical examples including periodic waves propagating over a submerged bar and non-hydrostatic lock exchange are used to demonstrate the capability and efficiency of the model. The simulation results are in good agreement with the analytical solution and experimental data.