scholarly journals Von Karman rotating nanofluid flow with modified Fourier law and variable characteristics in liquid and gas scenarios

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Muhammad Ramzan ◽  
Hina Gul ◽  
M. Mursaleen ◽  
Kottakkaran Sooppy Nisar ◽  
Wasim Jamshed ◽  
...  
Keyword(s):  
Salient Feature ◽  
Rotating Disk ◽  
Fourier Law ◽  
Mean Flow ◽  
Temperature Dependent ◽  
Nanofluid Flow ◽  
Heated Disk ◽  
The Mean ◽  
Convective Boundaries ◽  
Source Sink

AbstractThis investigation aims to explore the temperature-dependent variable characteristics of viscosity, and thermal conductivity with modified Fourier law in a nanofluid flow over a rotating disk. The uniqueness of the envisioned mathematical model is improved with the additional impacts of the chemical reaction, non-uniform source/sink, and convective boundaries. The salient feature of the existing problem is to discuss the whole scenario with liquid and gas thermo-physical characteristics. The graphical depiction is attained for arising pertinent parameter is attained by using Bvp4c a built-in MATLAB function. The visco-thermal conduct of the gases and liquids is examined by observing the mean flow and thermal distributions for the convectively heated disk. It is followed that liquid behaves more viscous with an increase in temperature in of the gas, but an opposing tendency can be seen for the liquid. The attained results are verified when compared with a published result.

Turbulence characteristics of the boundary layer on a rotating disk

1994 ◽  
Vol 266 ◽  
pp. 175-207 ◽  
Author(s):  
Howard S. Littell ◽  
John K. Eaton
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Reynolds Stress ◽  
Structural Model ◽  
Rotating Disk ◽  
Two Dimensional ◽  
Mean Flow ◽  
Velocity Correlation ◽  
Dimensional Boundary ◽  
The Mean

Measurements of the boundary layer on an effectively infinite rotating disk in a quiescent environment are described for Reynolds numbers up to Reδ2 = 6000. The mean flow properties were found to resemble a ‘typical’ three-dimensional crossflow, while some aspects of the turbulence measurements were significantly different from two-dimensional boundary layers that are turned. Notably, the ratio of the shear stress vector magnitude to the turbulent kinetic energy was found to be at a maximum near the wall, instead of being locally depressed as in a turned two-dimensional boundary layer. Also, the shear stress and the mean strain rate vectors were found to be more closely aligned than would be expected in a flow with this degree of crossflow. Two-point velocity correlation measurements exhibited strong asymmetries which are impossible in a two-dimensional boundary layer. Using conditional sampling, the velocity field surrounding strong Reynolds stress events was partially mapped. These data were studied in the light of the structural model of Robinson (1991), and a hypothesis describing the effect of cross-stream shear on Reynolds stress events is developed.

scholarly journals Transition to turbulence in the rotating disk boundary layer of a rotor–stator cavity

2018 ◽  
Vol 848 ◽  
pp. 631-647 ◽  
Author(s):  
Eunok Yim ◽  
J.-M. Chomaz ◽  
D. Martinand ◽  
E. Serre
Keyword(s):  
Boundary Layer ◽  
Similarity Solution ◽  
Rotating Disk ◽  
Transition To Turbulence ◽  
Mean Flow ◽  
Self Similarity ◽  
Mean Velocity ◽  
Global Mode ◽  
Spatial Growth ◽  
The Mean

The transition to turbulence in the rotating disk boundary layer is investigated in a closed cylindrical rotor–stator cavity via direct numerical simulation (DNS) and linear stability analysis (LSA). The mean flow in the rotor boundary layer is qualitatively similar to the von Kármán self-similarity solution. The mean velocity profiles, however, slightly depart from theory as the rotor edge is approached. Shear and centrifugal effects lead to a locally more unstable mean flow than the self-similarity solution, which acts as a strong source of perturbations. Fluctuations start rising there, as the Reynolds number is increased, eventually leading to an edge-driven global mode, characterized by spiral arms rotating counter-clockwise with respect to the rotor. At larger Reynolds numbers, fluctuations form a steep front, no longer driven by the edge, and followed downstream by a saturated spiral wave, eventually leading to incipient turbulence. Numerical results show that this front results from the superposition of several elephant front-forming global modes, corresponding to unstable azimuthal wavenumbers $m$, in the range $m\in [32,78]$. The spatial growth along the radial direction of the energy of these fluctuations is quantitatively similar to that observed experimentally. This superposition of elephant modes could thus provide an explanation for the discrepancy observed in the single disk configuration, between the corresponding spatial growth rates values measured by experiments on the one hand, and predicted by LSA and DNS performed in an azimuthal sector, on the other hand.

Measurements of Mean Flow Velocity Beyond a Rotating Disk

1971 ◽  
Vol 93 (2) ◽  
pp. 199-204 ◽  
Author(s):  
R. C. Chanaud
Keyword(s):  
Asymptotic Theory ◽  
Flow Region ◽  
Rotating Disk ◽  
Mean Flow ◽  
Mean Velocity ◽  
Comparison With Experiment ◽  
Disk Plane ◽  
The Mean ◽  
Momentum Integral ◽  
Technique Comparison

Measurements were made of the mean velocity components of the turbulent flow field just beyond the edge of a thin disk rotating in its own plane. An approximate analysis was made of the turbulent strongly swirling radial jet flow region by recourse to the momentum integral technique. Comparison with experiment indicated that approximate similarity of both the tangential and radial velocity components was achieved in a few disk thicknesses. The angle of the flow from radial in the disk plane compared fairly well with that predicted by the present analysis but poorly with the exact asymptotic theory. Nearly discrete frequency vortex shedding at the disk edge was detected by pressure-correlation measurements just outside the boundary layer.

Carbon nanotubes suspended dusty nanofluid flow over stretching porous rotating disk with non-uniform heat source/sink

2021 ◽  
pp. 1-10
Author(s):  
R. Naveen Kumar ◽  
Hogarehally Basavarajappa Mallikarjuna ◽  
Nirmala Tigalappa ◽  
R. J. Punith Gowda ◽  
Deepak Umrao Sarwe
Keyword(s):  
Carbon Nanotubes ◽  
Heat Source ◽  
Rotating Disk ◽  
Nanofluid Flow ◽  
Uniform Heat ◽  
Source Sink

Effect of Temperature Dependent Viscosity on MHD Radiative Nanofluid Flow Caused by Heated/Cooled Cone

2017 ◽  
Vol 14 (1) ◽  
pp. 821-828 ◽  
Author(s):  
C. S. K Raju ◽  
N Sandeep ◽  
M. E Ali
Keyword(s):  
Skin Friction Coefficient ◽  
Effect Of Temperature ◽  
Nonlinear Thermal Radiation ◽  
Temperature Dependent ◽  
Nanofluid Flow ◽  
Temperature Dependent Viscosity ◽  
Shooting Technique ◽  
Variation Parameter ◽  
Dependent Viscosity ◽  
Source Sink

In this study, we investigated the temperature dependent viscosity effect on magnetohydrodynamic nanofluid flow caused by a heated/cooled cone in the presence of nonlinear thermal radiation and irregular heat source/sink. The transformed governing equations using similarity variables are solved numerically using Runge-Kutta based shooting technique. We demonstrated solutions for Al2O3-water and TiO2-water nanofluid cases. The effects of various dimensionless parameters on velocity and temperature profiles along with the skin friction coefficient and the local Nusselt number are discussed and presented with the help of graphs and tables. It is found that the viscous variation parameter help to control the velocity as well as the temperature field and regulates the friction factor and heat transfer rate.

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