As the push for carbon-neutral transport continues, aviation sector is facing increasing pressure to reduce its carbon footprint. Furthermore, commercial air traffic expected resume continuous growth experienced until pandemic, highlighting need reduced emissions. The use of alternative fuels plays a key role in achieving future emission goals, while also lowering dependency on fossil fuels. so-called sustainable (SAF), which encompass bio and synthetic fuels, are currently most viable...

The objective of the presentwork is to investigate application a sinusoidal leading edge design ofmicro air vehicles. Wind-tunnel tests wings with low aspect ratios 1 and 1.5, rectangular planforms, five distinct edges [four one baseline (straight) for each ratio] have been conducted. Reynolds numbers 70,000 140,000 analyzed. For higher number, proper combination amplitude andwavelength can lead substantial increase in lift angles attack greater than stall angle. Maximum coefficient gains...

SUMMARY Lid‐driven cavity flow at moderate Reynolds numbers is studied here, employing a mesh‐free method known as Smoothed Particle Hydrodynamics (SPH). In detailed study of this benchmark, the incompressible SPH approach applied together with particle shifting algorithm. Additionally, new treatment for no‐slip boundary conditions developed and tested. The use aforementioned numerical solid walls leads to significant improvements in results respect other simulations carried out similar...

The unsteady, incompressible, moderate Reynolds number flow past a rectangular cavity is experimentally and numerically investigated. Laser-Doppler anemometry, visualization unsteady numerical simulation using fully second-order accuracy in time space, were the tools employed to meet this purpose. Large-amplitude organized oscillations are reported occur investigated geometry due fluid-dynamic instability. Detailed predictions clearly show that instability process involves complex coupling...

Summary An innovative inflow/outflow boundary treatment has been proposed to be used in smoothed particle hydrodynamics (SPH). Among other strategies, it involves the use of extended regions at open sections and a procedure enforce mass continuity constraint, as well minimize outflow reflections. This methodology coupled with modified ‘particle shifting’ algorithm, so that robustness method could ensured high Reynolds number regimes. Confined flow around square cylinder an selected problem...

The spray characteristics of angled liquid injection into subsonic crossflows were experimentally investigated. experiments conducted using water as the test and included variations nozzle angle, air velocity crossflow, flow rate. An initial assessment performed with aid a visualization technique revealed that overall jet penetration, breakup length, atomization quality are significantly affected by angle and, to lesser extent, liquid-to-air momentum flux ratio. Subsequently, detailed...

and back portion of the airfoil is shown in Figs. 2b 2c, respectively. The smooth transition grid from one type to another decency at sharp corners between close surfaces are clearly shown, which indicate excellent compatibility communication two strategies as controlled by a common background grid. was generated using Silicon Graphics IRIS 4D/210 VOX workstation. code's performance about 360 triangles/s on that workstation 2350 Cray Y-MP. total turnaround time required for generating around...

Condensation trails and contrail cirrus are currently responsible for the largest contribution to radiative forcing in aviation sector, yet they have lifetimes of only a few hours. Their much shorter when compared long-lived greenhouse gases makes them ideal implementation short-term mitigation measures. The use Sustainable Aviation Fuel (SAF) instead regular jet fuel has been associated reduction soot particle emissions, leading decrease initial ice crystal numbers contrails, but also...

The present study describes the performance of a novel combustor model for gas turbines. working principle this is based on establishment large recirculation zone in combustion chamber, where part inlet air mixed with products. Efficient mixing achieved by use high-velocity jets. Six different geometries have been analyzed under nonreacting and reacting conditions at atmospheric pressure. Laser-Doppler anemometry was employed to characterize mean velocity turbulent kinetic energy fields as...

Summary In this work, a dynamic procedure for local particle refinement to be used in smoothed hydrodynamics (SPH) is presented. The algorithm able consistently produce successive levels of splitting accordance flow‐based criterion. It has been applied together with accurate and robust formulations variable spatial resolution the framework semi‐implicit, truly incompressible scheme SPH. Different test cases have considered assess capabilities advantages proposed procedure, namely, laminar...

The use of various modeling approaches for the numerical simulation low-Reynolds-number flow past wings finite span with leading-edge protuberances is studied at pre- and poststall operating conditions. Variants Reynolds-averaged Navier–Stokes simulations (including transitional modeling) detached-eddy (involving different options shielding boundary layer from limiter), as well a correction, are considered. An assessment capabilities exhibited by these carried out, based on detailed...

This work is focused on the study of sprays produced by pressure atomizers single-hole type when subjected to air crossflows at atmospheric pressure. The was carried out in a wind tunnel. Prior spray characterization, airflow inside tunnel evaluated with aid laser Doppler anemometry. were first characterized using shadowgraphy technique, which allowed for qualitative evaluation overall quality atomization. Subsequently, use phase anemometry performing detailed measurements droplet diameters...

jetsandaidedbythespeci! cgeometryofthecombustionchamber.Itattemptstoimprovefurtherthehigh-ef! ciency low-emissions performance of combustion equipments by adopting as much possible some the ameless characteristics, such distributed reaction and approach to spontaneous ignition conditions. The combustor exhibits stable operation over a relatively wide range operating conditions and, at speci! c conditions, NOx level is below 10 ppm. Spatial distributions mean velocity turbulent kinetic...

Over the last decade, Airborne Wind Energy (AWE) innovation has been evolving with development of several prototypes by various companies/research institutions. AWE crosswind systems may differ in electricity generation mode, wing type, take-off/landing approaches and control mechanisms, to name a few. Each system characteristics which enhance their performance regarding key factors exploration at expense penalizing others. Hence, deciding for most appropriate possible implementation,...

Confined vortex breakdown generated by a rotating cone within closed cylindrical container has been studied both numerical simulation and experimental techniques. A comprehensive investigation of the various flow regimes carried out visualization. From laser–Doppler measurements entire field (three velocity components) detailed maps time-averaged structures for single double have constructed. Three-dimensional time-dependent simulations steady unsteady performed. Steady fields obtained at...

Abstract Several open boundary conditions (OBCs) are compared and evaluated in the framework of SIMPLE algorithm using staggered non‐staggered grid systems. The benchmark laminar flow test cases used for OBC evaluation Poiseuille‐Benard a channel stratified backward‐facing step flow. investigated OBCs linear explicit space extrapolation, Orlanski's monochromatic wave, pressure extrapolation. extrapolation treatment unsteady steady flows, respectively, yield little reflection has proved to be...

Detached eddy simulations have been performed for both infinite and finite wings using a sinusoidal leading edge passive stall control at Reynolds number of 160,000. The global effect this geometrical modification was initially assessed in terms aerodynamic characteristics, namely lift drag. Detailed analyses the flow topology obtained through visualization instantaneous vortical structures. numerical demonstrated ability catching bi-periodic pattern reported published experiments wings....