Small-scale wind energy portable turbine (SWEPT)

Design and experimental verification of a high efficiency small wind energy portable turbine (SWEPT)

Purpose – The purpose of this paper is to achieve high‐performance aerofoils that enable delayed stall conditions and achieve high lift to drag ratios.Design/methodology/approach – The unsteady Reynolds averaged Navier‐Stokes equations are employed in conjunction with a shear stress transport (κ‐ω) turbulence model. A control equation is designed and implemented to determine the temporal response of the actuator. A rotating element, in the form of an actuator disc, is embedded on the leading edge of NACA 0012 aerofoil, to inject momentum into the wake region. The actuator disc is rotated at different angular speeds, for angles of attack (α) between 00 and 240.Findings – Phenomena such as flow separation, wake vortices, delayed stall, wake control, etc. are numerically investigated by means of streamlines, streaklines, isobars, etc. Streamwise and cross‐stream forces on the aerofoil are obtained. The influence of momentum injection parameter (ξ) on the fluid flow patterns, and hence on the forces acting on...

CFD simulation of momentum injection control past a streamlined body

This article investigates numerically the effects on turbulence in two important flow regimes – fully developed channel flow and flow past a NACA 0012 airfoil, using the commercial software – FLUENT 6.3. The solution accuracy is explored via a sensitivity study of mesh type and quality effects, employing different element types (e.g. quadrilateral and triangular). The significance of this article is to elucidate the effects of enhancement wall treatment and standard wall function on the turbulent boundary layer. Furthermore, three different turbulence models have been utilized in this study (k−e, re-normalization group (RNG), and shear stress transport
(SST) k−ω). The numerical solutions have been compared with available direct numerical simulation (DNS) and experimental data and very good correlation has been achieved. In addition, the statistical turbulence results related to the RNG turbulence model are shown to yield much
closer correlation with DNS and experimental data. The effect of Reynolds number (Reτ = 590 and Reτ = 2320) is studied for the channel flow regime. The near wall resolution is examined in detail by controlling in the y+ value. A particularly important objective in this study is to highlight the importance of validation in computational fluid dynamics (CFD) turbulence simulations and
sustaining a high degree of accuracy, aspects which are often grossly neglected with industrial CFD software. The authors therefore hope to provide some guidance to applied aerodynamicists utilizing CFD in future studies.

Numerical investigations of wall-bounded turbulence:

This paper discusses the aerodynamics characteristics of Blended Wing Body — Baseline II E2, unmanned aerial vehicle aircraft. A computational method, Computational Fluid Dynamic (CFD) Star CCM+ software has been performed to obtain the aerodynamics characteristic of the BWB. The aerodynamic characteristics prediction of BWB-Baseline II E2 aircraft was obtained through CFD analysis using unstructured mesh and standard one — equation turbulence model, Spalart-Allmaras was selected in the investigations. Lift coefficient (CL), drag coefficient (CD) and moment coefficient (CM) were studied at flight condition of Mach 0.1 (∼34 m/s) at different angles of attack, α. The CFD results were compared with the experimental result. The results show the trend of lift curves are similar at the linear region (α = −10° to 7°) but at the higher angle of attack the trends become nonlinear. The drag coefficient for CFD simulations is greater than experimental result and there are differences in pitching moment curves between CFD simulation and experiment data which the experiment data shows a steep curve than simulation.

The aerodynamics performance of Blended Wing Body Baseline-II E2

Computational study into the flow field developed around a cascade of NACA 0012 airfoils

Summary Seismic pre-stack inversion is a tool used to predict the petroelastic properties from the seismic data which are further used to extract information about seismic lithology and pore fluids. When seismic waves travel through the subsurface layers, there are many factors, for example, fluids relative motion, particle friction, thin layer scattering, etc. which are responsible for the seismic energy dissipation and can be characterized as the viscoelastic behavior of the material. Ultimately it affects incident angle-dependent amplitudes and the seismic resolution of the data and therefore it is important to take it into consideration. The current study provides an inversion workflow based on the gradient-descent optimization method to extract the viscoelastic quality factors by the inversion of pre-stack seismic data. The adjoint-based gradient solution for the viscoelastic properties is derived and presented in this study. 

N. Ahmed

Papers

Computational study into the flow field developed around a cascade of NACA 0012 airfoils

Gradient Descent Optimization Method for AVO Inversion in Viscoelastic Media