Received: February 02, 2017 Revised: March 13, 2017 Accepted: May 19, 2017 Abstract: Introduction: Bridge scour is one of the major causes of bridge failure. Prediction of the maximum depth and shape of local scour plays an important role in bridge design and maintenance. In this paper, k-ε turbulent model combined with wall function was employed and complex flow fields are exhibited. The bed l...

Laboratory tests were carried out to assess the local scour by three-dimensional wall jets from a square crosssection nozzle. To this end, three different tailwater depths were used and the jet expansion ratio was held greater than ten. Velocity measurements were conducted using a one component laser Doppler anemometer. The jet exit Reynolds number was maintained to 1x10 and this value can be c...

Many permanent spillway tunnels of high earth-rock dams are rebuilt from their diversion tunnels. Scour problem is focused because of their high water head and velocity. Energy Approach is a new method to Estimating Scour and is used here to estimate the depth of scour downstream of 1 spillway tunnel of Zipingpu Project. The method is illustrated working fine by comparing its results with data ...

Pile scour may cause instability to the structures they support. Ensuring a safe and economically sound design is essential for the wider community. Although much laboratory research has been carried out on scour at pile groups, there are still significant gaps in prediction formulae. This study has been conducted to develop a formula for scour at pile arrangements of non-uniform spacing. The s...

the effect of grain size, tailwater depth and grain froude number on local scour caused by submerged horizontal jets issuing below a sluice gate was investigated. noncohesive sediments with two gradations downstream of a horizontal apron were used in the experiments. the experiments were carried out at different inflow froude numbers and a range of tailwater depth from low to high submergence. ...

Flood-induced scour is the principal cause of bridge failure worldwide. Nevertheless, risk assessment still based on visual inspections, which may be affected by human errors and cannot performed during flood peaks. This problem, together with simplifications in estimation, might misclassification risk, unnecessary closures or recourse to avoidable mitigation measures. Structural-health-monitor...

An improved neuro-fuzzy based group method of data handling using the particle swarm optimization (NF-GMDH-PSO) is developed as an adaptive learning network to predict the localized scour downstream of a sluice gate with an apron. The input characteristic parameters affecting the scour depth are the sediment size and its gradation, apron length, sluice gate opening, and the flow conditions upst...

In the present work, the efficiency of single and double collar in reducing scour rate and depth around cylindrical bridge piers was studied experimentally. In order to reduce the strength of wake vortices, different numbers of bars were also installed at the downstream face of the pier in combination with a single collar. The best result was achieved for double collar when the collars were ins...

The interaction between ocean environment and pile structure is so complex that despite considerable laboratory as well as prototype studies estimation of scour depth and its geometry in a generalized and accurate form are still difficult to make. One of the reasons underlying this uncertainty could be the limitation of the statistical curve fitting technique, commonly employed to analyse the c...

Flow and scour around a vertical cylinder exposed to current are investigated by using a three-dimensional numerical model based on incompressible Reynolds-averaged Navier-Stokes equations. The model incorporates (i) k-ω turbulence closure, (ii) vortex-shedding processes, (iii) sediment transport (both bed and suspended load), as well as (iv) bed morphology. The influence of vortex shedding and...