Balaji T. Ranganathan

Bio: Balaji T. Ranganathan is an academic researcher. The author has contributed to research in topics: Boundary layer & Internal flow. The author has an hindex of 1, co-authored 1 publications receiving 85 citations.

Stabilization and destabilization of channel flow by location of viscosity-stratified fluid layer

Abstract: The stability of the channel flow of two fluids of different viscosities with a mixed layer in between is demonstrated to be qualitatively different from both interface dominated flows and stratified flows. More important, this flow displays unexpected changes in stability when the mixed layer overlaps the critical layer of the disturbance: this feature can be exploited for flow control. When these layers are distinct, the flow is mildly destabilized when the less viscous fluid is in the outer region. When the layers overlap, however, there is an order of magnitude stabilization of the flow. The reverse occurs when the more viscous fluid is in the outer region. This behavior may be explained by the balance of stresses in the critical layer.

Nanofibers and their applications in tissue engineering.

Abstract: Developing scaffolds that mimic the architecture of tissue at the nanoscale is one of the major challenges in the field of tissue engineering. The development of nanofibers has greatly enhanced the scope for fabricating scaffolds that can potentially meet this challenge. Currently, there are three techniques available for the synthesis of nanofibers: electrospinning, self-assembly, and phase separation. Of these techniques, electrospinning is the most widely studied technique and has also demonstrated the most promising results in terms of tissue engineering applications. The availability of a wide range of natural and synthetic biomaterials has broadened the scope for development of nanofibrous scaffolds, especially using the electrospinning technique. The three dimensional synthetic biodegradable scaffolds designed using nanofibers serve as an excellent framework for cell adhesion, proliferation, and differentiation. Therefore, nanofibers, irrespective of their method of synthesis, have been used as scaffolds for musculoskeletal tissue engineering (including bone, cartilage, ligament, and skeletal muscle), skin tissue engineering, vascular tissue engineering, neural tissue engineering, and as carriers for the controlled delivery of drugs, proteins, and DNA. This review summarizes the currently available techniques for nanofiber synthesis and discusses the use of nanofibers in tissue engineering and drug delivery applications.

Interaction of cells and nanofiber scaffolds in tissue engineering.

Abstract: Nanofibers and nanomaterials are potentially recent additions to materials in relation to tissue engineering (TE). TE is the regeneration of biological tissues through the use of cells, with the aid of supporting structures and biomolecules. Mimicking architecture of extracellular matrix is one of the challenges for TE. Biodegradable biopolymer nanofibers with controlled surface and internal molecular structures can be electrospun into mats with specific fiber arrangement and structural integrity for drug delivery and TE applications. The polymeric materials are widely accepted because of their ease of processability and amenability to provide a large variety of cost-effective materials, which help to enhance the comfort and quality of life in modern biomedical and industrial society. Today, nanotechnology and nanoscience approaches to scaffold design and functionalization are beginning to expand the market for drug delivery and TE is forming the basis for highly profitable niche within the industry. This review describes recent advances for fabrication of nanofiber scaffolds and interaction of cells in TE.

Instabilities in Viscosity-Stratified Flow

Abstract: This review highlights the profound and unexpected ways in which viscosity varying in space and time can affect flow. The most striking manifestations are through alterations of flow stability, as established in model shear flows and industrial applications. Future studies are needed to address the important effect of viscosity stratification in such diverse environments as Earth's core, the Sun, blood vessels, and the re-entry of spacecraft.

Linear stability analysis and numerical simulation of miscible two-layer channel flow

Abstract: The stability of miscible two-fluid flow in a horizontal channel is examined. The flow dynamics are governed by the continuity and Navier–Stokes equations coupled to a convective-diffusion equation for the concentration of the more viscous fluid through a concentration-dependent viscosity. Our analysis of the flow in the linear regime delineates the presence of convective and absolute instabilities and identifies the vertical gradients of viscosity perturbations as the main destabilizing influence in agreement with previous work. Our transient numerical simulations demonstrate the development of complex dynamics in the nonlinear regime, characterized by roll-up phenomena and intense convective mixing; these become pronounced with increasing flow rate and viscosity ratio, as well as weak diffusion.