Applied Mechanics and Materials Vols. 641-642

Abstract: Lateral distributions of depth-averaged velocity in open compound channels with submerged vegetated floodplains are analyzed, based on an analytical solution to the depth-integrated Reynolds-Averaged Navier-Stokes equation with a term included to account for the effects of vegetation. The cases of open channels are: rectangular channel with submerged vegetated corner, and compound channel with submerged vegetated floodplain. The present paper proposes a method for predicting lateral distribution of the depth-averaged velocity with submerged vegetated floodplains. The method is based on a two-layer approach where flow above and through the vegetation layer is described separately. An experiment in compound channel with submerged vegetated floodplain is carried out for the present research. The analytical solutions of the three cases are compared with experimental data. The corresponding analytical depth-averaged velocity distributions show good agreement with the experimental data.

Abstract: The dynamic analysis of a turbine blade is carried out. The pre-stress due to rotation and fluid-thermal-structure coupling effect are considered. At first flow analysis and thermal analysis on the blade and corresponding stator-rotor blade passage are conducted to acquire the flow field and body temperature field of blade. Then stress in the blade is analyzed considering pressure and temperature in a static condition, and the matrix for pre-stress effect and an additional matrix due to the external temperature and pressure loading are obtained. And so the dynamic equation of the blade system including the pre-stress effect and the coupling effect is established. The frequencies and vibration modes of the blade system in six different coupling conditions are obtained by using of ANSYS and CFX. It is found that the fluid-thermal-structural coupling field has a significant influence on the blade natural frequencies. Also, the impact of temperature on frequency is embodied more in the change of material elastic modulus E with temperature than in the thermal stress caused by temperature gradient.

Abstract: Water jet technology is widely used in dredging engineering. Since there will be large deformation of sand bed during erosion by water jet, the calculation mesh will be distorted seriously and lead to simulation failure. In order to solve the problem, the Smoothed Particle Hydrodynamics (SPH) method was used to simulate the dynamic process of high speed water jet erosion of sand bed. The simulation process and key techniques were discussed, the effect of water jet velocity and water jet target distance on the depth of eroded pit was studied. The results show that SPH could describe the process intuitively and the evolution of particle velocity field and sand bed pressure field could be shown clearly. The depth of the pit varies with time linearly. The decrease of water jet target distance and the increase of the water jet velocity deepen the eroded pit.

Abstract: Used the numerical method, considered the rising speed of head of seepage deformation, with the aid of the method of particle flow in micro layer to study the occurrence and development of the law of seepage failure. Numerical simulation was designed based on the study of the theory. Conducting piping tests of the soil samples by controlling water head. The results show that, the effects of loaded once on the orifice area was large, and also the most insecure. And the test result verifies the correctness of theoretical analysis. The results are valuable to further probing into the piping mechanism in sandy soils.

Abstract: This paper simulates the characteristics of 2D U-shape bend flow using nonlinear k~ε closure turbulence model in the software CCHE2D. Furthermore, we get the pictures about transverse slope of water surface, the transverse velocity distribution and transverse section water level variation. With comparison and analysis, the numerical simulation results are agreement with the experimental data measured by De Vriend. Simulating the movement of 2D bend flow with the software CCHE, an accurate flow basic characteristic can be obtained.

Abstract: Landslide generated waves in the reservoir were investigated in a three-dimension physical model based on the generalized Froude similarity. The tests included the following several influence factors: still water depth, still water width, landslide volume, landslide fall, slide angle. The waves generated process, as a complex solid-air-water phenomena, is composed of landslide entering water, the first wave generation, air-spray group forming, the second wave generation, wave run-up, wave propagation. Empirical equations base on most of experiments of the first maximum wave amplitude, the second maximum wave amplitude, the maximum wave run-up are described by multiple regressions of following dimensionless quantities: the relative slide Froude number, the relative landslide volume, the relative still water wide.

Abstract: Vegetated roof technique is becoming increasingly popular, particularly in highly urbanized areas, among the Sustainable Urban Drainage Systems (SUDS) for urban stormwater management. Several studies [1,2] have shown that vegetated roofs may significantly reducing the runoff volume and hydrograph peaks, as well as slowing the contribution to the urban drainage network.This study proposes a conceptual model to predict the hydraulic behavior of a full-scale physical model of a vegetated roof. The model idealizes the vegetated roof as a system consisting of three individual components in series. A mass balance equation is applied to each block, taking into account the specific physical phenomena occurring in each module [3]. The model is validated using dataset observed from the monitoring campaign carried out on the prototype of a full-scale vegetated roof.This study aims to provide quantitative information about the hydraulic performance of vegetated roofs, and identify the most sensitive parameters for describing the hydraulic behavior. The results show a good ability of the model to fit the measured data.

Abstract: The free-surface-pressurized-flow is a complicated water-air two phase flow in the spillway tunnel, which should be studied in the engineering practice. This flow pattern existed from open flow to pressure flow with the submerged depth increasing, which has obvious pulsing pressure. The flow transformation and pressure distributions were observed and studied in this paper.

Abstract: Characters of water delivery in winter of long distance canal system were analyzed and studied. Ice disasters threatening the operation safety such as ice jam and ice dam were introduced. Then a detailed summary of water delivery mode in winter was done to avoid ice disasters, and the mode of delivering water under a juxtaposed ice cover was recommended. At last operation and control of long distance canal system by stages in winter was proposed.

Abstract: The size distribution of carrying capacity as the forefront of current non-equilibrium transportation of non-uniform suspended sediment research was introduced. The nonequilibrium transportation of suspended sediment concept was further studied. The preliminary calculations and verification of the size distributions of carrying capacity and effective bed material under nonequilibrium transportation condition were given after derived by Qiwei Han. The formula is tested by experimental data and the theoretical results are consistent with the measured values.