Welcome Note from Editor-in-Chief

It is with great pleasure that I write this editorial to welcome you to the first issue of this new International journal, “Pakistan Biomedical Journal” (PBMJ). The topics covered by the journal are certainly broad and interesting. Biomedical science is a collection of applied sciences that help us understand, research, and innovate within the field of healthcare. It includes disciplines like molecular biology, clinical virology, bioinformatics, and biomedical engineering, among others. It's designed to apply the biological sciences to advance not only individual health but also the area of public health. Biomedical Research can help health professions better understand things like the human body and cell biology, making advances in our understanding of epidemics, health initiatives, and human health in the age of longer life expectancy. It aids our understanding of infectious disease and provides research opportunities into some of our most troubling health issues. The journal will continue to publish high quality clinical and biomedical research in health and disease later in life. Peer review will remain a vital component of our assessment of submitted articles.I am very happy to have a team of excellent editors and editorial board members from the top international league covering in depth the related topics. They will ensure the highest standards of quality for the published manuscripts and, at the same time, keep the process time as short as possible. We hope to bring best researches in the field of biomedical sciences that may serve as a guideline in health awareness, understanding the mechanisms and its management in future.   We definitely look forward to receiving your excellent studies to making PBMJ synonymous with high quality in the biomedical science domain.

Investigation of Various Sediment and Flow Parameters upon Three Dimensional Flow Using Numerical Model

The aim of this research work was to investigate and increase the understanding of three dimensional flow behavior under changing conditions of flow and sediments. The goal was achieved by using a 3D Computational Fluid Dynamics model FLUENT. The geometry selected for this study is that of a meandering compound channel. The parameters which were changed in this research work include the width of floodplain along with main channel width, overbank flow depth, incoming discharge, bed slope of the main channel and floodplains and roughness of the channel and floodplains. The research work was conducted by using different turbulence models. Among them are standard k - e , Re-normalization Group (RNG) theory based k - e and k - w turbulence models. These three models were applied for one case. Once the capability of k - e model was established after comparison with results of other models, then only k - e was used in the remaining part of the work. The data obtained from a physical model study in the laboratory was used for the validation of simulated results. The validation was done through a comparison of observed and calculated values of depth averaged velocities, total discharge at a section & point velocities. After validation, the CFD model was used to predict and investigate those aspects of flow which were difficult to get through experiments and for which experimentation was not conducted in the laboratory. These aspects include turbulence intensity, turbulent kinetic energy, pressure distribution on different cross sections of the channel and surface velocity magnitudes. As far as the sediments study is concerned, the Lagrangian particle tracking technique was used to predict the changes in bed levels at apex of the meander wavelength. Sediment particles with different diameters were used for this purpose. A total of eight flow cases were considered for the study of flow field. Each case varies from the other on the basis of (i) geometry or (ii) bed slope or (iii) depth of overbank flow or a combination of these. This work also proved the capability of standard k - e turbulence closure models in prediction of 3D overbank flows. Keywords: Sediment transport, CFD modeling, Flood flows, Numerical techniques, Turbulent kinetic energy.