Journal of the Indian Institute of Science最新文献

The accumulation of contaminants in aquatic sediments poses a significant threat to ecosystem health and human well-being. This review paper aims to provide a comprehensive overview of contaminated sediment management and development of Sediment Quality Guidelines (SQG). The paper includes national and international scenario about contaminated sediment issues focusing on the sources, contaminants, and their environmental and economic impacts followed by characterization of contaminated sediments, reference methods, the need and development of sediment quality guidelines. Sediment management includes remediation strategies, remediation processes, discussion about the factors affecting remediation processes and the potential for reusing treated sediments. Further, use of nano remediation with nano Zero Valent Iron (nZVI) and bioremediation process are discussed in detail including advantages, disadvantages, and possible approaches. Valorisation of contaminated sediment is the latest trend and has been discussed with the approaches to Life Cycle Analysis (LCA) of contaminated dredged sediments, which include consideration of environmental impact and carbon emissions involved in various remediation techniques and a comparison of the same to have an informed decision about the remedial measures to take.

Magnetic driven targeted drug delivery (TDD) involves the manipulation of magnetic drug carriers, such as nano/micro particles or bubbles, within the body using external magnetic fields to precisely reach the intended target location. This method is utilized in treating severe illnesses like cancerous tumors and nervous disorders, offering higher efficacy with reduced drug dosages and side effects. While numerous studies have simulated magnetic driven TDD, comprehensive reviews remain scarce. This article presents an extensive review of computational/numerical work done on magnetic driven TDD utilizing both microbubbles and non-bubbles (nano/micro particles) within human vasculature and lung airways. The study aims to analyze the drug delivery problem from physical and numerical perspectives. Key highlights include artery wall models (rigid, flexible, or porous), models of force acting on particles, relevant governing equations, discussions on parameters of interest and their effects on drug delivery efficacy. Finally, the article briefly outlines common trends observed in magnetic driven TDD problems and their underlying physical principles.

This review article traces the development of the Volume-Of-Solid immersed boundary method, referred to as VOS-IB, over the last decade. Starting from its simple beginnings inspired by the Volume-Of-Fluid method in multiphase flow, we discuss the evolution of this technique and its extensions for problems in Boussinesq and non-Boussinesq flows, conjugate heat transfer, multi-fluid flows, fluid–structure interactions, and turbulent flows. A critical assessment of the strengths and limitations of the VOS-IB technique is presented and possible directions for future research, both in terms of development of the method and its applications, are outlined.

In the human body, blood acts as a transporter of oxygen and other nutrients as well as carbon dioxide and other waste materials to and from all the organs. Therefore, continuous supply of blood to all the organs is critical for proper functioning of the human body. Blood is a complex fluid and has more than 40% flexible particles which include red blood cells, white blood cells, platelets and other proteins suspended in a water-like fluid, plasma. The dynamics of blood flow, known as haemodynamics, is critical in the development, diagnosis and treatment planning of vascular diseases and design and development of cardiovascular devices. Whilst the most advanced flow measurement techniques such as X-ray imaging, magnetic resonance imaging and ultrasound imaging are used in the diagnosis and treatment of vascular diseases, it is not possible to obtain the complete information of pressure and velocity field experimentally via in vivo methods. Therefore, in silico methods or computational modelling techniques are being increasingly employed not only to understand the haemodynamics but also for use in the clinical setting. Whilst blood is treated as a homogeneous, single-phase fluid in several studies, it is possible to capture several features of the flow of blood only by modelling it as a multiphase fluid. A number of approaches have been adopted to model multiphase flow of blood. A broad categorisation can be based on whether the cell boundary is captured explicitly, e.g. immersed boundary method, or the phases are treated as interpenetrating and two or more phases can exist simultaneously at a point, e.g. Euler–Euler method. In the literature, both the approaches have been adopted to model the flow of blood. Particle-based methods, such as smoothed particle hydrodynamics and dissipative particle dynamics have also been employed by researchers to study the complex interactions associated with the flow of blood. In this article, we discuss different multiphase modelling approaches and their application in the haemodynamics modelling.

Understanding and predicting multiphase flows is of great relevance due to the ubiquitous nature of such flows in both nature and in many industrial applications. Rapid development of high speed computers and problem-specific algorithms in the last 2 decades has enabled the study of multiphase flows through numerical simulations. In this paper, we give a brief overview of different methods used in direct numerical simulations of two-phase flows. In particular, we focus on the volume of fluid (VOF) method used for locating and advecting the interface. VOF method is a mesh based interface capturing method in which a scalar function called void fraction field (which is the ratio of tracked fluid to the cell volume) is advected in order to track the interface position. A geometric VOF algorithm is detailed in this work. which strikes a balance between accuracy, ease of implementation and volume conservation on a structured grid. Another challenge in two-phase flow simulations is the inclusion of surface tension forces accurately. Here, we give a brief overview of Eulerian surface tension models and detail an approach balancing computational cost, curvature estimation and imposed timestep restriction. Finally, we discuss the most recent advances in VOF methods and outline the various numerical challenges we expect to encounter.

The design of micro aerial vehicles has been long inspired by biological flyers such as birds and insects. The aerodynamic principles of flapping wing flights are complex due to the rapid wing motion and the inherent complex vortex dynamics. Several experimental and numerical investigations have been carried out in the past decades to uncover the mechanisms responsible for the improved aerodynamic capability of flapping wings. This paper provides an overview of the aerodynamics of flapping insect wings. After providing a brief overview of the aerodynamics of a single wing, we discuss how the vortex dynamics are altered in the case of tandem wings. A significant challenge to designing a stable MAV is the environmental effects stemming from the gust and ground presence. In this paper, we present how the force generation is altered due to such effects. Moreover, we point out unsolved research questions on insect flight whose answers could greatly help to improve the design of flapping wing MAVs.

In this paper, we systematically review interface-driven mesh adaptation procedures for the phase-field modeling of fluid–structure interaction problems. One of the popular ways of handling fluid–structure interaction problems involving large solid deformations is the fully Eulerian approach. In this procedure, we use a fixed computational grid over which a diffused interface description can be used to evolve the fluid–structure boundary. The Eulerian solid representation and a diffuse interface method necessitate the use of adaptive mesh refinement to achieve reasonable accuracy for the problem at hand. We explore the usage of mesh refinement techniques for such FSI problems and focus specifically on interface-driven adaptivity. We present comparisons among various error indicators for the adaptive procedure of the unstructured mesh. We finally explore some possible future directions and challenges in the field.