CU Journal of Non-Linear Fluid Mechanics

Editorial Note

P G Siddheshwar — 2025-03-25

Study of chaos in Rayleigh-Benard convection of water-alumina nanofluid with heat source sink

C. Kanchana — 2025-03-25

Study of chaos in Rayleigh-Benard convection of a water-alumina nanofluid with internal heat source/sink is considered in the paper.
A generalized Buongiorno two-phase model is used for the formulation of the problem under the assumption of Boussinesque approximation 
and small-scale convective motion. By considering a minimal-mode Fourier representation, we arrive at the penta-model generalized 
Lorenz model. The largest lyapunov exponent and the Kaplan-Yorke dimension are used to capture commencement of chaos, windows of 
chaotic motion and periodic orbits. Inhibition/suppression of chaos due to the presence of nanoparticles and heat source/sink are 
discussed. Study on linear stability analysis is made for completeness.

Thermal Analysis of a Reactive Third Grade Fluid Film Flow on a Vertically Moving Heated Belt

Oluwole Daniel Makinde — 2025-03-25

Grasping the thermal behavior of a reactive non-Newtonian thin film flows on a vertically upward moving heated belt is crucial for refining predictive models used in engineering applications like coating and lubrication processes. This study investigates the thermal stability of a reactive third-grade fluid thin film flow on a heated moving belt with an adiabatic free surface. It assumes an exothermic reaction based on Arrhenius kinetics, while ignoring material consumption. The coupled system of nonlinear ordinary differential equations is solved using a perturbation approach combined with a specialized Hermite–Pade´ approximation technique. The paper investigates key features of the overall flow structure, including velocity and temperature fields, thermal criticality, and bifurcations.

Effects of Surface Roughness on Transient Viscoelastic Fluids Flow Driven by Peristaltic Pumping

Ashvani Kumar — 2025-03-25

Present study investigates the impact of sinusoidal surface roughness on the behaviour of viscoelastic fluid being transported in physiological vessels by peristaltic pumping, a vital mechanism in biological systems, and can be applied in industrial processes. Most of the biological surfaces are smooth however it is not complete smooth and some roughness is always present. To understand and examine the roughness effects and viscoelastic behaviour, a mathematical model is developed, incorporating a low Reynolds number and long-wavelength approximation. In this study, viscoelastic fluid behaviour is analysed by considering the Jeffrey model. The study focuses on the effects of the ratio of relaxation time to the retardation time and roughness height on key fluid characteristics, including axial velocity, pressure gradient, pressure distribution, volumetric flow rate and skin friction. The results reveal that increased surface roughness height leads to a reduction in fluid flow, as indicated by decreased axial velocity, volumetric flow rate and increased pressure gradient. Conversely, an increase in surface roughness height elevates skin friction, highlighting the additional resistance encountered by the fluid. These findings are critical for optimizing fluid transport systems that involve viscoelastic fluids, especially in applications where precise control of fluid dynamics is required. The insights gained from this study are particularly valuable for improving the analysis of fluid behaviour in medical diagnostics and other related fields.

Effect of Brinkman number on Chemically reactive Bi-viscous Bingham hybrid nanofluid flow across the penetrable sheet with mass transfer

S M Sachhin — 2025-03-25

The current work aims to analyze the impact of Brinkman number and variable MHD on Bi-viscous Bingham hybrid nanofluid flow across the penetrable sheet with heat transfer. Molybdenum disulfide (MoS₂) and Graphite oxide (GO) nanoparticles are dispersed in Sodium alginate (SA) to form a hybrid nanofluid. Using similarity conversions, the governing nonlinear PDEs for momentum, temperature, and concentration are transformed into ODEs along with the boundary condition. In the fluid region, the heat balance is kept conservative with a source/sink that relies on the temperature, and in the case of radiation, Bvp-4c, and shooting method to obtain the numerical solutions. Furthermore, the results of the current problem can be discussed by implementing a graphical representation with different factors, The results of the present analysis define that upsurging the inverse Darcy number decays the axial velocity, and increasing the thermal radiation raises the temperature. The current problem contains many industrial uses in technology and industrial processes, like Aerodynamics in vehicle design, blood flow in medicine, and oil and gas extraction.