62,651 research outputs found
INSET programmes in Kuwait: a national survey of stakeholder perception
No full textIn-service teacher training programmes, which is mentioned as INSET in this thesis, is considered by the different educational policies around the world as one of the most important and sensitive factors which has the potential to support and improve schools performance in a visible scale (Almazkoor, 2009; Alwan, 2000; Bayracki, 2009; Burns, 2005; Rakumako & LaugKsch, 2010; and Yigit, 2010). However, there is a need of designing and producing sustainable INSET programmes which are practical to the demands of specific contexts. The purpose of this research is to explore current INSET programmes provided to teachers in the public schools in the State of Kuwait and understand the perceptions of the respective teachers, heads of departments and head teachers.The nature of this research can be fallen under the pragmatic paradigm because it tries to connect the perceptions and reflections of teachers and school members to perceive a holistic picture of the targeted educational practice. Mixed methods approaches were used in this descriptive study, and one questionnaire and forty-five semi-structured interviews were conducted to explore the research participants’ perceptions on the quality, contributions and suggestions on present INSET programmes in Kuwait.Thirty sets of questionnaire were delivered to the teachers of the fifty primary, intermediate and secondary public schools of all six districts of Kuwait namely Alasema, Alfarwanya, Aljahra, Alahmadi, Hawalli and Mubarak Alkabeer. Teachers responded to the questionnaire and shared their opinions using both the Likert scale statements and open ended questions. Interviews were conducted with teachers, head of departments and head teachers to examine their perception in more elaborately about current INSET programmes in order to understand and explore their wider views and opinions. The sample was selected as a randomly selection in order to obtain a representative sampling and the reason for that was to gather a representative findings that can describe the population fairly.The data analysis procedure was completed through three phases. Firstly, quantitative data were collected via questionnaires from participants and questionnaires were then revised and treated by the SPSS system. The quantitative data were divided in a thematic way based on the research questions, and each theme has its own items that were set to answer that theme. The quantitative findings were then presented in tables as counts and percentages for each theme and its items. Secondly, qualitative data were collected from interviewees who were given coded in order to illustrate each one is voice. Data were then transcribed and categorized in a thematic way based on the research questions and literature review.Finally, each of the two methods was presented in a thematic manner with its findings and results and supported by each method. The aim is to combine and match the two methods as one theme and that support each other. The responses of the interviewees were allocated to the six major themes namely programme design PD, trainer competency TC, identifying and meeting needs IMN, impact I, feedback F and teacher willingness and rewards TWR. Analysis of the words, views and ideas from teachers, head of departments and head teachers were given full consideration based on the six themes. The interviewees showed deep and wider picture for current INSET programmes that support and enrich the questionnaire responses along the overall study. All the data from teachers, head of departments and head teachers indicated that there is a need to improve and reconstruct INSET programmes and the way they are designed and delivered.The findings of this research study showed agreement across all data collection tools concerning teachers and schools strong willingness to contribute and participate in plan and design INSET programmes. In addition, the findings also showed clear indications to the deficiencies and weakness of the current INSET programmes policy and practice in Kuwait and to provide teachers and schools with the authority to plan and design their own INSET programmes. It is also discovered that INSET programmes do not have a systematic follow up and evaluation by those who deliver it in Kuwait. Furthermore, there was no systematic rewards and incentives system for INSET programmes in Kuwait. This study reflects that in order to plan and design effective INSET programmes there is a need to allow teachers and their schools to contribute and participate in plan and design such programmes and to provide them with power
Effects of freestream trubulence on crossflow instability
No full textDirect numerical simulations (DNS) have been performed in order to investigate the interaction of freestream turbulence and crossflow generated instability on a swept wing. The experiments by [3] and [1] are selected as the reference cases. In those experiments the authors explore the interaction between different freestream turbulence characteristics and different roughness element characteristics. In the current study, isotropic homogenous freestream turbulence are generated following experimental parameters and then fed as the inflow boundary condition for DNS of flow over the wing. A spanwise array of roughness elements corresponding to the most unstable stationary modes are used to generate the crossflow vortices. The effects of the freestream turbulence on the crossflow instability and transition to turbulence are later studied
A Dynamic Subfilter-scale Stress Model for Large Eddy Simulations Based on Physical Flow Scales
No full textWe propose a new definition of the length scale in an eddy-viscosity model for large-eddy simulations (LES). This formulation extends and generalizes a previous proposal [Piomelli, Rouhi and Geurts, Proc. ETMM10, 2014], in which the LES length scale was expressed in terms of the integral length-scale of turbulence determined by the flow characteristics and explicitly decoupled from the simulation grid; this approach was named Integral Length-Scale Approximation (ILSA). As in the original ILSA, the model coefficient was determined by the user, and required to maintain a desired contribution of the unresolved, subfilter scales (SFS) to the global transport. We propose a local formulation (local ILSA) in which the model coefficient is local in space, allowing a precise control over SFS activity as a function of location. This new formulation preserves the properties of the global model; application to channel flow and backward-facing step verifies its features and accuracy
Large-eddy simulation of a separated flow with a sub-filter scale model based on the integral length-scale
No full textA new sub-filter scale model for large-eddy simulations, which uses a length-scale proportional to the integral scale of the turbulence instead of the grid resolution to parametrize the modelled stresses, will be assessed in the prediction of the flow of a boundary-layer over a rough surface, which includes separation and reattachment
Near Wall PIV-Measurements on the Windward Slope of a Hill
No full textThe turbulent flow over periodic hills was measured near to the wall, using planar Particle-Image-Velocimetry (PIV) at high spatial resolution. Our focus is on the near wall turbulence structure on the windward slope of the hill. For large-eddy simulation (LES) we suspect that, if this was not predicted accurately, it affects the prediction of the velocity profiles over the hill crest which in turn will affect the recirculation length downstream of the hill. Regarding the time averaged velocities, we were able to resolve the linear viscous region of the boundary layer. The velocity distribution and also the Reynolds stress does not comply with the law of the wall as it is valid for a turbulent boundary layer at equilibrium
Energy dissipation and flux laws for unsteady turbulence
No full textDirect Numerical Simulations of spatially periodic unsteady turbulence show that the high Reynolds number scalings of the instantaneous energy dissipation rate and interscale energy flux at intermediate wavenumbers are qualitatively different from the well-known cornerstone scalings of equilibrium turbulence where and are time-dependent rms velocity and integral length-scales. Instead, they both scale as where and are length and velocity scales characterizing initial/overall unsteady turbulence conditions
Direct numerical simulation of turbulent Couette-Poiseuille flow with zero skin friction
No full textThe near-wall scaling of mean velocity U(y) is addressed for the case of zero skin friction on one wall of a fully turbulent channel flow. The present DNS results can be added to the evidence in support of the conjecture that U is proportional to √yw in the region just above the wall at which the mean shear dU/dy = 0
Real-space Manifestations of Bottlenecks in Turbulence Spectra
No full textAn energy-spectrum bottleneck, a bump in the turbulence spectrum between the inertial and dissipation ranges, is shown to occur in the non-turbulent, one-dimensional, hyperviscous Burgers equation and found to be the Fourier-space signature of oscillations in the real-space velocity, which are explained by boundary-layer-expansion techniques. Pseudospectral simulations are used to show that such oscillations occur in velocity correlation functions in one- and three-dimensional hyperviscous hydrodynamical equations that display genuine turbulence
Braid Entropy of Faraday Waves driven 2D Turbulence
No full textWe report new experimental results that use tools from braid theory to characterize two-dimensional turbulent flows driven by Faraday waves. The average topological length of the material fluid lines is found to grow exponentially with time. It allows us to compute the braid’s topological entropy SBraid. We show that SBraid increases as the square root of the turbulence kinetic energy E ~ u^2, where u^2 is the horizontal velocity variance . At long times, the PDFs of Lbraid are positively skewed and present strong exponential tails
Mean flow generation by Görtler Vortices in a rotating annulus with librating side walls
No full textLongitudinal libration of the cylinder side walls of a rotating annulus in the supercritical regime induces a centrifugally unstable Stokes boundary layer which generates Görtler vortices only in a portion of a libration cycle. We show for the first time that these vortices propagate into the fluid bulk and generate an azimuthal mean flow which is retrograde (prograde) over the outer (inner) cylinder side wall. Direct numerical simulations (DNS) are carried out and Reynolds-averaged equations and kinetic energy budget of mean and fluctuating flow are used as diagnostic equations to discuss the generation mechanism and scaling behavior of the azimuthal mean flow in the fluid bulk
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