Critical values in transport phenomena for curved power-law sheet utilizing Al2O3-Cu/water hybrid nanoliquid: Model prediction and stability analysis

2019 ◽  
Vol 30 (11) ◽  
pp. 2787-2800 ◽  
Author(s):  
Sanjay Kumar ◽  
Pramod Kumar Sharma ◽  
Puneet Rana
Keyword(s):  
Stability Analysis ◽  
Power Law ◽  
Model Prediction ◽  
Transport Phenomena ◽  
Critical Values

Non-Newtonian slender drops in a nonlinear extensional flow

2019 ◽  
Vol 877 ◽  
pp. 561-581 ◽  
Author(s):  
Moshe Favelukis
Keyword(s):  
Stability Analysis ◽  
Power Law ◽  
Analytical Solutions ◽  
Viscosity Ratio ◽  
Extensional Flow ◽  
Shear Thinning ◽  
Newtonian Liquid ◽  
Creeping Flow ◽  
Stationary States ◽  
Power Law Index

In this theoretical report we explore the deformation and stability of a power-law non-Newtonian slender drop embedded in a Newtonian liquid undergoing a nonlinear extensional creeping flow. The dimensionless parameters describing this problem are: the capillary number $(Ca\gg 1)$, the viscosity ratio $(\unicode[STIX]{x1D706}\ll 1)$, the power-law index $(n)$ and the nonlinear intensity of the flow $(|E|\ll 1)$. Asymptotic analytical solutions were obtained near the centre and close to the end of the drop suggesting that only Newtonian and shear thinning drops $(n\leqslant 1)$ with pointed ends are possible. We described the shape of the drop as a series expansion about the centre of the drop, and performed a stability analysis in order to distinguish between stable and unstable stationary states and to establish the breakup point. Our findings suggest: (i) shear thinning drops are less elongated than Newtonian drops, (ii) as non-Newtonian effects increase or as $n$ decreases, breakup becomes more difficult, and (iii) as the flow becomes more nonlinear, breakup is facilitated.

scholarly journals Avalanches and power law behavior in aortic dissection propagation

2020 ◽  
Vol 6 (21) ◽  
pp. eaaz1173 ◽  
Author(s):  
Xunjie Yu ◽  
Béla Suki ◽  
Yanhang Zhang
Keyword(s):  
Cardiovascular Disease ◽  
Extracellular Matrix ◽  
Aortic Dissection ◽  
Power Law ◽  
Model Prediction ◽  
Strain Energy ◽  
Quantitative Agreement ◽  
High Morbidity ◽  
Failure Mechanics ◽  
Microscopic Features

Aortic dissection is a devastating cardiovascular disease known for its rapid propagation and high morbidity and mortality. The mechanisms underlying the propagation of aortic dissection are not well understood. Our study reports the discovery of avalanche-like failure of the aorta during dissection propagation that results from the local buildup of strain energy followed by a cascade failure of inhomogeneously distributed interlamellar collagen fibers. An innovative computational model was developed that successfully describes the failure mechanics of dissection propagation. Our study provides the first quantitative agreement between experiment and model prediction of the dissection propagation within the complex extracellular matrix (ECM). Our results may lead to the possibility of predicting such catastrophic events based on microscopic features of the ECM.

scholarly journals Stability Analysis of Gravity Currents of a Power-Law Fluid in a Porous Medium

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Sandro Longo ◽  
Vittorio Di Federico
Keyword(s):  
Porous Medium ◽  
Stability Analysis ◽  
Linear Stability ◽  
Power Law ◽  
Gravity Currents ◽  
Two Dimensional ◽  
Continuum Spectrum ◽  
Fluid Behavior ◽  
Self Similar ◽  
Flow Domain

We analyse the linear stability of self-similar shallow, two-dimensional and axisymmetric gravity currents of a viscous power-law non-Newtonian fluid in a porous medium. The flow domain is initially saturated by a fluid lighter than the intruding fluid, whose volume varies with time astα. The transition between decelerated and accelerated currents occurs atα= 2 for two-dimensional and atα= 3 for axisymmetric geometry. Stability is investigated analytically for special values ofαand numerically in the remaining cases; axisymmetric currents are analysed only for radially varying perturbations. The two-dimensional currents are linearly stable forα< 2 (decelerated currents) with a continuum spectrum of eigenvalues and unstable forα= 2, with a growth rate proportional to the square of the fluid behavior index. The axisymmetric currents are linearly stable for anyα< 3 (decelerated currents) with a continuum spectrum of eigenvalues, while forα= 3 no firm conclusion can be drawn. Forα> 2 (two-dimensional accelerated currents) andα> 3 (axisymmetric accelerated currents) the linear stability analysis is of limited value since the hypotheses of the model will be violated.

scholarly journals Effect of Viscous Dissipation in Heat Transfer of MHD Flow of Micropolar Fluid Partial Slip Conditions: Dual Solutions and Stability Analysis

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4617 ◽  
Author(s):  
Liaquat Ali Lund ◽  
Zurni Omar ◽  
Ilyas Khan ◽  
Seifedine Kadry ◽  
Seungmin Rho ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Differential Equations ◽  
Thermal Radiation ◽  
Viscous Dissipation ◽  
Micropolar Fluid ◽  
Fluid Velocity ◽  
Dual Solutions ◽  
Critical Values ◽  
Partial Slip ◽  
Shrinking Sheet

In this study, first-order slip effect with viscous dissipation and thermal radiation in micropolar fluid on a linear shrinking sheet is considered. Mathematical formulations of the governing equations of the problem have been derived by employing the fundamental laws of conservations which then converted into highly non-linear coupled partial differential equations (PDEs) of boundary layers. Linear transformations are employed to change PDEs into non-dimensional ordinary differential equations (ODEs). The solutions of the resultant ODEs have been obtained by using of numerical method which is presented in the form of shootlib package in MAPLE 2018. The results reveal that there is more than one solution depending upon the values of suction and material parameters. The ranges of dual solutions are S ≥ S c i , i = 0 , 1 , 2 and no solution is S < S c i where S c i is the critical values of S . Critical values have been obtained in the presence of dual solutions and the stability analysis is carried out to identify more stable solutions. Variations of numerous parameters have been also examined by giving tables and graphs. The numerical values have been obtained for the skin friction and local Nusselt number and presented graphically. Further, it is observed that the temperature and thickness of the thermal boundary layer increase when thermal radiation parameter is increased in both solutions. In addition, it is also noticed that the fluid velocity increases in the case of strong magnetic field effect in the second solution.

scholarly journals A stability analysis of the power-law steady state of marine size spectra

2010 ◽  
Vol 63 (4) ◽  
pp. 779-799 ◽  
Author(s):  
Samik Datta ◽  
Gustav W. Delius ◽  
Richard Law ◽  
Michael J. Plank
Keyword(s):  
Steady State ◽  
Stability Analysis ◽  
Power Law ◽  
Size Spectra
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