A5090268652- Rheology and Fluid Dynamics Studies
- Fluid Dynamics and Turbulent Flows
- Fluid Dynamics and Vibration Analysis
- Blood properties and coagulation
- Fluid Dynamics and Thin Films
- Surfactants and Colloidal Systems
Indian Institute of Technology Kanpur
2018-2021
Newtonian pipe flow is known to be linearly stable at all Reynolds numbers. We report, for the first time, a linear instability of pressure-driven viscoelastic fluid, obeying Oldroyd-B constitutive equation commonly used model dilute polymer solutions. The shown exist numbers significantly lower than those which transition turbulence typically observed flow. Our results qualitatively explain experimental observations in solutions rates where absent. discussed here should form stage hitherto...
A modal stability analysis shows that pressure-driven pipe flow of an Oldroyd-B fluid is linearly unstable to axisymmetric perturbations, in stark contrast its Newtonian counterpart which stable at all Reynolds numbers. The dimensionless groups govern are the number, elasticity and ratio solvent solution viscosity. mode has a phase speed close base-state maximum over entire region relevant parameter space, implying belongs class viscoelastic center modes. Unlike transition dominated by...
A linear stability analysis of plane Poiseuille flow an upper-convected Maxwell (UCM) fluid, bounded between rigid plates separated by a distance $2L$ , has been carried out to investigate the interplay elasticity and inertia on stability. The is governed following dimensionless groups: Reynolds number $Re=\unicode[STIX]{x1D70C}U_{max}L/\unicode[STIX]{x1D702}$ $E\equiv W/Re=\unicode[STIX]{x1D706}\unicode[STIX]{x1D702}/(\unicode[STIX]{x1D70C}L^{2})$ where $W=\unicode[STIX]{x1D706}U_{max}/L$...
A modal stability analysis shows that plane Poiseuille flow of an Oldroyd-B fluid becomes unstable to a `center mode' with phase speed close the maximum base-flow velocity, $U_{max}$. The governing dimensionless groups are Reynolds number $Re = \rho U_{max} H/\eta$, elasticity $E \lambda \eta/(H^2\rho)$, and ratio solvent solution viscosity $\eta_s/\eta$; here, $\lambda$ is polymer relaxation time, $H$ channel half-width, $\rho$ density. For experimentally relevant values (e.g., \sim 0.1$...