EPTT 2022

13th Spring School on Transition and Turbulence

Study of Non-Newtonian Fluid Flow Stability Modeled by LPTT

Submission Author: Andreza Beatriz , SP
Co-Authors: Andreza Beatriz, Leandro Franco de Souza, Laison Junio da Silva Furlan, Matheus Tozo de Araujo
Presenter: Andreza Beatriz

doi://10.26678/ABCM.EPTT2022.EPT22-0033

 

Abstract

Several flows of practical interest are from viscoelastic fluids and it is often desirable to know whether these flows propagate in a laminar or turbulent state. Although the hydrodynamics of viscoelastic fluids are strongly affected by the balance between forces inertial and elastic flows, the effect of elasticity on the stability of inertial flows has not been fully established. The Linear Stability Theory (LST) provides a framework to obtain information about the rate of growth with respect to frequency for a certain base flow. This theory is based on the continuity and Navier-Stokes equations, considering some hypotheses about the flow and the form of propagation of the disturbances. It predicts under what conditions instabilities form and provides information on spatial and temporal scales, identifying the type of instability that occurs. Stability analysis relates directly to the transition to turbulence, providing information about what conditions make a flow unstable and prone to become turbulent. The importance of the project lies in the development of a curve diagram stability neutrals for viscoelastic flows using the Linear Stability Theory. The contribution of scientific research is innovative, as it aims to aggregate knowledge and promote the scientific and technological improvement of laminar-turbulent transition, development of codes and the construction of efficient techniques in the simulation of incompressible flows of viscoelastic fluids. Thus, this work contributes with current results in the sense to provide an important tool in verifying the stability of two-dimensional flows using the LPTT fluid. In the present work, we study the transition laminar-turbulent, in which the convection of Tollmien-Schlichting waves will be investigated for the two-dimensional Poiseuille incompressible flow for a viscoelastic fluid, using the Phan-Thien Tanner linear constitutive equation (PTT). The Theory of Linear Stability (LST) is used to verify the stability of viscoelastic fluid flows to non-stationary perturbations. In LST analysis the equations are linearized for a fluid viscoelastic. In order to evaluate neutral stability curves, different simulations Numerical measurements are performed by varying the dimensionless parameters for the fluid flow viscoelastic and compared with the Newtonian fluid.

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