17,294 research outputs found
Personality and learning styles towards the practical-based approach
An enduring question for educational research is the result of individual deviations in the efficacy of learning. The individual learning differences that have been much explored relate to differences in personality, learning styles, strategies and conceptions of learning. This article studies the personality and the learning style profile exhibited by students in a practical based approach of vocational courses. The relationship between personality and learning styles among students was assessed as the students got along through the curriculum. The analysis show that students are more oriented towards an active learning mode in a practical-based approach. Given a specific instruction, some people will learn more effectively than others due to their individual personality and learning styles. This study will help a vocational instructor and advisors to understand their students and to design instruction that can benefit students to accomplish a respectable performance in their learning process
Thermal receptivity of free convective flow from a heated vertical surface: linear waves
Numerical techniques are used to study the receptivity to small-amplitude thermal disturbances of the boundary layer flow of air which is induced by a heated vertical flat plate. The fully elliptic nonlinear, time-dependent Navier–Stokes and energy equations are first solved to determine the steady state boundary-layer flow, while a linearised version of the same code is used to determine the stability characteristics. In particular we investigate (i) the ultimate fate of a localised thermal disturbance placed in the region near the leading edge and (ii) the effect of small-scale surface temperature oscillations as means of understanding the stability characteristics of the boundary layer. We show that there is a favoured frequency of excitation for the time-periodic disturbance which maximises the local response in terms of the local rate of heat transfer. However the magnitude of the favoured frequency depends on precisely how far from the leading edge the local response is measured. We also find that the instability is advective in nature and that the response of the boundary layer consists of a starting transient which eventually leaves the computational domain, leaving behind the large-time time-periodic asymptotic state. Our detailed numerical results are compared with those obtained using parallel flow theory
MHD free convection-radiation interaction in a porous medium - part I : numerical investigation
A numerical investigation of two dimensional steady magnetohydrodynamics heat and mass transfer by
laminar free convection from a radiative horizontal circular cylinder in a non-Darcy porous medium is presented
by taking into account the Soret/Dufour effects. The boundary layer conservation equations, which are parabolic
in nature, are normalized into non-similar form and then solved numerically with the well-tested, efficient,
implicit, stable Keller–Box finite-difference scheme. We use simple central difference derivatives and averages at
the mid points of net rectangles to get finite difference equations with a second order truncation error. We have
conducted a grid sensitivity and time calculation of the solution execution. Numerical results are obtained for the
velocity, temperature and concentration distributions, as well as the local skin friction, Nusselt number and
Sherwood number for several values of the parameters. The dependency of the thermophysical properties has been
discussed on the parameters and shown graphically. The Darcy number accelerates the flow due to a
corresponding rise in permeability of the regime and concomitant decrease in Darcian impedance. A comparative
study between the previously published and present results in a limiting sense is found in an excellent agreement
Mean Temperature Profiles in Turbulent Thermal Convection
To predict the mean temperature profiles in turbulent thermal convection, the
thermal boundary layer (BL) equation including the effects of fluctuations has
to be solved. In Shishkina et al., Phys. Rev. Lett. 114 (2015), the thermal BL
equation with the fluctuations taken into account as an eddy thermal
diffusivity has been solved for large Prandtl-number fluids for which the eddy
thermal diffusivity and the velocity field can be approximated respectively as
a cubic and a linear function of the distance from the plate. In the present
work we make use of the idea of Prandtl's mixing length model and relate the
eddy thermal diffusivity to the stream function. With this proposed relation,
we can solve the thermal BL equation and obtain a closed-form expression for
the dimensionless mean temperature profile in terms of two independent
parameters for fluids with a general Prandtl number. With a proper choice of
the parameters, our predictions of the temperature profiles are in excellent
agreement with the results of our direct numerical simulations for a wide range
of Prandtl numbers from 0.01 to 2547.9 and Rayleigh numbers from 10^7 to 10^9.Comment: 8 pages, 4 figure
Radiation and viscous dissipation effects for the Blasius and Sakiadis flows with a convective surface boundary condition
This study is devoted to investigate the radiation and viscous dissipation effects on the laminar boundary layer about a flat-plate in a uniform stream of fluid (Blasius flow), and about a moving plate in a quiescent ambient fluid (Sakiadis flow) both under a convective surface boundary condition. Using a similarity variable, the governing nonlinear partial differential equations have been transformed into a set of coupled nonlinear ordinary differential equations, which are solved numerically by using shooting technique along side with the sixth order of Runge-Kutta integration scheme and the variations of dimensionless surface temperature and fluid-solid interface characteristics for different values of Prandtl number Pr, radiation parameter NR, parameter a and the Eckert number Ec, which characterizes our convection processes are graphed and tabulated. Quite different and interesting behaviours were encountered for Blasius flow compared with a Sakiadis flow. A comparison with previously published results on special cases of the problem shows excellent agreement
A numerical study of the longitudinal thermoconvective rolls in a mixed convection flow in a horizontal channel with a free surface
This paper presents a numerical study of three-dimensional laminar mixed
convection within a liquid flowing on a horizontal channel heated uniformly
from below. The upper surface is free and assumed to be flat. The coupled
Navier-Stokes and energy equations are solved numerically by the finite volume
method taking into account the thermocapillary effects (Marangoni effect). When
the strength of the buoyancy, thermocapillary effects and forced convective
currents are comparable and ,
the results show that the development of instabilities in the form of steady
longitudinal convective rolls is similar to those encountered in the
Poiseuille-Rayleigh-B\'enard flow. The number and spatial distribution of these
rolls along the channel depend on the flow conditions. The objective of this
work is to study the influence of parameters, such as the Reynolds, Rayleigh
and Biot numbers, on the flow patterns and heat transfer characteristics. The
effects of variations in the surface tension with temperature gradients
(Marangoni effect) are also considered
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