Abstract: Prediction of maximum local scour is necessary for
the safety and economical design of the bridges. A number of
equations have been developed over the years to predict local scour
depth using laboratory data and a few pier equations have also been
proposed using field data. Most of these equations are empirical in
nature as indicated by the past publications. In this paper attempts
have been made to compute local depth of scour around bridge pier in
dimensional and non-dimensional form by using linear regression,
simple regression and SVM (Poly & Rbf) techniques along with few
conventional empirical equations. The outcome of this study suggests
that the SVM (Poly & Rbf) based modeling can be employed as an
alternate to linear regression, simple regression and the conventional
empirical equations in predicting scour depth of bridge piers. The
results of present study on the basis of non-dimensional form of
bridge pier scour indicate the improvement in the performance of
SVM (Poly & Rbf) in comparison to dimensional form of scour.
Abstract: Present study was aimed to develop a discharge
measuring device for irrigation and laboratory channels. Experiments
were conducted on sharp edged constricted flow meters having four
types of width constrictions namely 2:1, 1.5:1, 1:1 and 90o in the
direction of flow. These devices were made of MS sheets and
installed separately in a rectangular flume. All these four devices
were tested under free and submerged flow conditions. Eight
different discharges varying from 2 lit/sec to 30 lit/sec were passed
through each device. In total around 500 observations of upstream
and downstream depths were taken in the present work. For each
discharge, free submerged and critical submergence under different
flow conditions were noted and plotted. Once the upstream and
downstream depths of flow over any of the device are known, the
discharge can be easily calculated with the help of the curves
developed for free and submerged flow conditions. The device
having contraction 2:1 is the most efficient one as it allows maximum
critical submergence.
Abstract: The present paper attempts to investigate the
prediction of air entrainment rate and aeration efficiency of a free
overfall jets issuing from a triangular sharp crested weir by using
regression based modelling. The empirical equations, Support vector
machine (polynomial and radial basis function) models and the linear
regression techniques were applied on the triangular sharp crested
weirs relating the air entrainment rate and the aeration efficiency to
the input parameters namely drop height, discharge, and vertex angle.
It was observed that there exists a good agreement between the
measured values and the values obtained using empirical equations,
Support vector machine (Polynomial and rbf) models and the linear
regression techniques. The test results demonstrated that the SVM
based (Poly & rbf) model also provided acceptable prediction of the
measured values with reasonable accuracy along with empirical
equations and linear regression techniques in modelling the air
entrainment rate and the aeration efficiency of a free overfall jets
issuing from triangular sharp crested weir. Further sensitivity analysis
has also been performed to study the impact of input parameter on the
output in terms of air entrainment rate and aeration efficiency.