Department of Civil & Infrastructure Engineering

&ldquo;IIT Jodhpur is committed to impart quality education to facilitate the creation of qualified, competent and responsible human resources to meet the emerging technological challenges of the world. It is working towards creating an equitable learning platform that is positive, accessible and effective in the face of the modern societal and scientific advancements.

Flexibility in curriculum, in all its academic programs, encompassing elements of teaching, research, creativity, innovation and entrepreneurship is the most unique feature of IIT Jodhpur. The Department of Science and Technology (DST), under the National Mission on Cyber Physical Systems, has identified IIT Jodhpur as a Technology &amp; Innovation Hub in the area of Augmented Reality and Virtual Reality. The institute has also been nominated as the coordinator for the Jodhpur City and Knowledge Cluster by the Office of Principal Scientific Adviser, Government of India.

The sprawling 852-acre IIT Jodhpur campus is a majestic tribute to the deep-rooted diverse cultural heritage of the region. The campus is an architectural masterpiece, which is slated to become an international exemplar of sustainability with net-zero energy, and advanced water and waste management strategies.&rdquo;

IIT Jodhpur

McGill University (Canada)

Transport of surface-modified iron nanoparticles through model subsurface porous media

World University root node

ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY

Role of aggregation and straining in transport of polymer-stabilized zerovalent iron nanoparticles in granular media

A. F. Shields carried out his doctoral research study on sediment transport in the Technischen Hochschule Berlin. He is well known for proposing a useful diagram, known as Shields diagram, that provides the criterion for the threshold of sediment entrainment, which is an essential requirement for the determination of sediment motion in a loose boundary stream. His diagram becomes famous and is most frequently referred in the literature. It has provided an enormous inspiration to initiate a sizable number of researches over last seven decades. Since his pioneering work, numerous attempts have so far been made to quantify the required flow condition (threshold boundary shear stress) for the beginning of sediment movement. The important laboratory experimental and theoretical studies on threshold of sediment entrainment under steady stream flows are briefly summarized, as a perspective review, highlighting the empirical formulations and semitheoretical analyses. A special attention is given towards the influence of the turbulent bursting on sediment entrainment. Latest experiments evidence the mechanism of sediment entrainment is governed by the sweep events. © Springer-Verlag Berlin Heidelberg 2011.

GeoPlanet: Earth and Planetary Sciences

Entrainment Threshold of Loose Boundary Streams

Geophysical flows of practical interest encompass turbulent boundary layer flows. The velocity profile in turbulent flows is generally described by a log- or a power-law applicable to certain zones of the boundary layer, or by wall-wake law for the entire zone of the boundary layer. In this study, a novel theory is proposed from which the power-law velocity profile is obtained for the turbulent boundary layer flow. The new power-law profile is based on the conservation of mass and the skin friction within the boundary layer. From the proposed theory, analytical expressions for the power-law velocity profile are presented, and their Reynolds-number dependency is highlighted. The velocity profile, skin friction coefficient and boundary layer thickness obtained from the proposed theory are validated by the reliable experimental data for zero-pressure gradient turbulent boundary layers. The expressions for Reynolds shear stress and eddy viscosity distributions across the boundary layer are also obtained and validated by the experimental data. © 2011 Institute of Geophysics.

Acta Geophysica

Power-law velocity profile in turbulent boundary layers: An integral reynolds-number dependent solution

This experimental study is devoted to quantification of the near-bed turbulence characteristics at an entrainment threshold of noncohesive sediments. Near the bed, the departure in the distributions of the observed time-averaged streamwise velocity from the logarithmic law is more for immobile beds than for entrainment-threshold beds. In the Reynolds shear stress distributions, a damping that occurs near the bed for sediment entrainment is higher than that for immobile beds. Quadrant analysis reveals that in the near-bed flow zone, ejections and sweeps on immobile beds cancel each other, giving rise to the outward interactions, whereas sweeps are the dominant mechanism toward sediment entrainment. The bursting duration for entrainment-threshold beds is smaller than that for immobile beds. On the other hand, the bursting frequency for entrainment-threshold beds is larger than that for immobile beds. The third-order correlations indicate that during sediment entrainment, a streamwise acceleration associated with a downward flux and advection of streamwise Reynolds normal stress is prevalent. The streamwise and the downward vertical fluxes of turbulent kinetic energy (TKE) increase with sediment entrainment. The TKE budget proves that for sediment entrainment, the pressure energy diffusion changes drastically to a negative magnitude, indicating a gain in turbulence production. © 2011 American Society of Civil Engineers.

Fulltext

Journal of Hydraulic Engineering

Near-bed turbulence characteristics at the entrainment threshold of sediment beds

Colloids and Surfaces A: Physicochemical and Engineering Aspects 390 (1-3 {\ldots}

Systematic comparison of the size, surface characteristics and colloidal stability of zero valent iron nanoparticles pre-and post-grafted with common polymers

Journal of contaminant hydrology 118 (3-4)

Assessment of transport of two polyelectrolyte-stabilized zero-valent iron nanoparticles in porous media

Universal probability density functions (PDFs) of two-dimensional turbulent velocity fluctuations, Reynolds shear stress and conditional Reynolds shear stresses in flows over smooth and rough beds are obtained using a Gram-Charlier series expansion based on the exponential distribution. To include skewness and kurtosis, the series is truncated up to moments of Order 4. The distributions of PDFs obtained theoretically and from the experimental data are in agreement. The conditional Reynolds shear stresses related to the ejections and sweeps are well represented by the exponential distribution, but those related to the outward and inward interactions depart from the theoretical distributions. © 2010 International Association for Hydro-Environment Engineering and Research.

Journal of Hydraulic Research

Universal probability distributions of turbulence in open channel flows

The paper presents a study on the influence of gravity on the incipient motion and the bed-load transport of sediment. The computation of critical bed-shear stress is revisited considering the balance of forces (hydrodynamic forces and submerged self-weight) acting on a solitary sediment particle lying on an arbitrary sloping bed. Modified effective bed-shear stress and the corresponding critical bed-shear stress, which are defined to assess the incipient motion of sediment in the direction of resultant force, are applied for the estimation of bed-load transport rate in the direction of resultant force. The sediment transport induced by the gravitational force, which is oblique to the direction of the drag force induced by flow, is incorporated into the bed-load transport equation. This modified model provides a reasonable prediction of the critical bed-shear stress and the bed-load transport rate. The model is validated by experimental data. It can be applied to steep slopes and can also avoid the problem of singularity that arises in numerically calculation of sediment transport rate. Additionally, the vectorial transport rate obtained in the model calculation can be implemented in a numerical simulation of channel bed evolution. © 2010 ASCE.

Sediment transport on arbitrary slopes: Simplified model

Double-averaged turbulence characteristics in a uniform flow over a gravel bed are studied. The log-law for the velocity is preserved above the interfacial sublayer, while the velocity within that sublayer follows a polynomial law. The Reynolds shear stress distribution within the roughness sublayer has a considerable damping. A quadrant analysis suggests that the sweeps become the prevalent mechanism within the interfacial sublayer. Within the interfacial sublayer, the quadrant plots of the form-induced velocities form a tilted pseudo-elliptical shape, suggesting that the fluid undergoes a cyclic process of upward-streamwise deceleration and downward-streamwise acceleration. An upward-downstream flux of the turbulent kinetic energy is prevalent over the entire flow depth, while a downward-upstream flux corresponding to sweep events is the mechanism within the interfacial sublayer. The energy budget indicates that the turbulent production, dissipation and diffusion, having attained their peaks, reduce sharply within the interfacial sublayer, and the pressure energy diffusion changes drastically to a negative magnitude below the virtual bed level. © 2010 International Association for Hydro-Environment Engineering and Research.