Research Projects

Fluid flow in bounded or unbounded geometry consisting of porous-fluid multi-layer channel flow has been observed in industries and geophysical applications. For instance, industrial crossflow filtration systems, transpiration cooling of rocket engines, etc. These flows admit hydrodynamic instabilities, due to which laminar flow ultimately becomes turbulent. Instabilities arise mainly due to the interaction between fluid-particle and porous-structure interactions. Such instabilities in the multi-layer channel have been a topic of study for decades. Because of the importance of multi-layer porous channel flow, the proposal is based on these flows' modal and non-modal stability analysis. Several physical quantities, such as porosity, inhomogeneity, mean permeability, anisotropy, layer-depth ratios, etc., significantly affect the flow's stability. Moreover, inertial effects may also change the stability characteristic of porous channel flows. This calls for studies on the stability of anisotropic porous multi-layer channel flow having finite permeability, porosity, inhomogeneity, and inertia. One of the aims of this proposal is to find critical values of the parameters which affect flow stability. In particular, the effect of anisotropy, permeability, and inhomogeneity will be studied in detail. Note that there are some channel flows where instability is desirable (e.g., heat ex-changer devices). For some others, the fluid flow must always be stable (e.g., manufacturing composite materials by RFI, and aircraft or motor car production). The expected output and outcome of the proposed research work provide a possible way of designing confined geometry to control flow instabilities in multi-layer flows and provide control parameters to set up laboratory experiments. The results for particular cases will be validated with the current results. With this broad idea in mind, we set the following objectives: (1) The pressure-driven multi-layer channel flow will be modeled by considering generalized models for porous medium. (2) The linear stability and non-modal analyses will be performed. A parametric study will be carried out to understand the effect of inertia, anisotropy, permeability, and inhomogeneity on the stability of a wide parameter range. (3) To design small equipment involving multi-layer porous channel flow, one needs to identify the critical parameters. The proposed study will provide a list of the critical parameters for the widely used porous materials, such as Fomemetal, Aloxide, etc. These critical values also help in relevant experimental setups. (4) Similar stability analyses will be carried out for the multi-layer non-Newtonian porous-fluid flows, which have importance in blood flow.