Increment Of Coefficient Research Articles

Optimisation of straight plate upstream deflector for the performance enhancement of vertical axis wind turbine at low, medium and high regimes of tip speed ratios

Location and geometry optimisations of Straight Plate Upstream Deflector (SPUD) for performance enhancement of a three-straightbladed Vertical Axis Wind Turbine (VAWT) are carried out at three regimes of tip speed ratios (TSRs). Results analysis reveals that SPUD location has significant effect on the power coefficient ( Cp) increment of VAWT. Placing two SPUDs both upward and downward in upstream of VAWT can achieve the highest Cp improvement at all regimes of TSRs. Overall, placing SPUD in upstream of VAWT can improve the Cp value at all regimes of TSRs, but the percentage of improvement can vary. The largest Cp improvement of 126.7% is achieved at low regime of TSRs, while at the medium and high regimes of TSRs, Cp improvements decrease to 52.7% and 52.5%, respectively. Increasing the width of SPUD can increase the average VAWT Cp improvement by 2.83% at all regimes of TSRs.

Review on Vortex Generators Mounted on Airfoil to Improve the Aerodynamic Performance

In aircrafts lift is the most important factor which depends on wing performance. But during the cruising flight when the angle of attack increases there is change in the aerodynamic factors such as lift and drag forces due to the boundary layer (BL) separation. To delay or avoid this boundary layer separation and improve the aerodynamic performance of the wing vortex generators were introduced. Vortex generators helps to keep the boundary layer attached to the wings upper surface. In previous decades much study is done to control this BL on the different types of airfoils i.e. symmetrical or unsymmetrical. This review is based on study related to improve these parameters so that there will be increment in lift coefficient and reduction in drag coefficient. To overcome these parameters appropriate size, shape, length, position and incidence angle, etc should be investigated to find out the suitable one. These investigations can be performed as numerical based using software simulation and also by experimental approach in a wind tunnel. The main practical advantage of these vortex generators is to reduce parasite drag on airfoil and increase the lift force, they are also demonstrated to be critically important in other applications also.

Numerical investigation on heat and mass transfer characteristics of ice slurry in pulsating flow

In this paper, the heat transfer enhancement of ice slurry in a horizontal pipe with constant heat flux has been investigated numerically. The model is validated with the experimental results from the literature. Then the axial distribution of the heat transfer coefficient, the bulk and wall temperature and the ice volume fraction are obtained. The factors that affect the heat transfer coefficient are analyzed. Furthermore, the heat transfer efficiency of ice slurry in pulsating flow is compared with that in steady state. It is found that the heat transfer efficiency of ice slurry can be significantly improved by pulsating flow. The maximum increment of cycle-averaged heat transfer coefficient reaches 34.32%. Moreover, the degrees of heat transfer enhancement increase with increasing pulsating frequency, relative amplitude of velocity, ice particle diameter and ice volume fraction, and decrease with increasing cycle-averaged velocity. And the heat transfer is more efficient to ice slurry with large particles and ice volume fraction under the pulsating flow conditions. The pulsating frequency is suggested to be not more than 10π Hz. Finally, the correlation for predicting cycle-averaged Nusselt number of ice slurry in pulsating flow is established, and obtaining the reasonably good prediction results.

Biochemical and physical–chemical characterisation of leaf proteins extracted from Cichorium endivia leaves

This study provides a detailed characterisation of a leaf protein concentrate (LPC) extracted from Cichorium endivia leaves using a pilot scale process. This concentrate contains 74.1% protein and is mainly composed of Ribulose-1,5-BISphosphate Carboxylase/Oxygenase (RuBisCO). We show that the experimentally determined extinction coefficient (around 5.0 cm−1 g−1 L depending on the pH) and refractive index increment (between 0.27 and 0.39 mL g−1) are higher than the predicted ones (about 1.6 cm−1 g−1 L and 0.19 mL g−1, respectively). In addition, the UV–visible absorption spectra show a maximum at 258 nm. These data suggest the presence of non-protein UV-absorbing species. Chromatographic separation of the concentrate components in denaturing conditions suggests that RuBisCO SC may be covalently bounded to few phenolic compounds. Besides, the solubility of LPC proteins is higher than 90% above pH 6. Such high solubility could make LPC a good candidate as a functional food ingredient.

An Efficient Scheme for Acoustic Echo Canceller Implementation Using Offset Binary Coding

This article presents an efficient design and implementation scheme for a low-area and low-power acoustic echo canceller. The design employs the block least mean square algorithm-based adaptive filter (ADF) using offset binary coding. The proposed approach first formulates the ADF by splitting the matrix–vector multiplication into smaller ones. Each of them is then realized with lookup tables and shift accumulate units with offset terms. An efficient scheme is suggested to update the offset terms from the corresponding lookup tables. In addition, a novel optimization scheme is proposed based on the grouping of partial products (PPs) and moving windows. The PPs are generated in two parallel styles using adders, multiplexers, and registers. The optimized architecture is shared to compute both the filter output and coefficient increment terms in every iteration. The fixed-point quantization model for the architecture is also discussed. Accuracy measure is defined to characterize the proposed design and compare it with the Cramer–Rao lower bound. Simulations are carried out to evaluate the performance of the proposed design. Field-programmable gate array implementation results and application-specific integrated circuit synthesis show that the proposed design outperforms the state-of-the-art architectures.

Investigation of laminar forced convection heat transfer of nanofluids through flat plate solar collector

The paper analyzes laminar forced convection heat transfer for both single and mixture phase models utilizing Al2O3-water and CuO-water nanofluids as the working fluid and examines the effect of internal fins in the collector tubes in order to improve collector efficiency. A physical model with governing equations has been defined. Finite volume method has been utilized for discretizing governing equations and finite element method has been utilized for three-dimensional analysis of solar plate model with finned tubes. Convective heat transfer coefficient, Nusselt number and shear stress have been analyzed for Reynolds numbers from 200 to 700 with 0-5% volume fractions of nanofluid. Moreover, the efficiency of the collector has been investigated for constant flow rates from 0.02 to 0.04 mL/s and variable overall heat loss coefficient for the same range of volume fractions of nanofluid. It has been found that increment of shear stress and heat transfer coefficient occurred with the increment of concentration of nanoparticles and the Reynolds number. Investigation of particle size has not shown any notable variation with the mixture phase model. Mixture-phase model gives comparatively lower values due to the reduction of viscosity near the wall. Noticeable increment of efficiency has been observed by changing working fluid from Al2O3-water to CuO-water which has been further improved by utilizing variable overall heat loss coefficient. Efficiency increases up to 6.5% and 8.7% than the base fluid for utilizing Al2O3-water and CuO-water nanofluid respectively. Additionally, utilizing internal fins to the riser tubes, the efficiency increases up to 11%.

Thermal Characterization of Coolant Maxwell Type Nanofluid Flowing in Parabolic Trough Solar Collector (PTSC) Used Inside Solar Powered Ship Application

Parabolic trough solar collectors (PTSCs) are generally utilized to reach high temperatures in solar-thermal applications. The current work investigates entropy production analysis and the influence of nano solid particles on a parabolic trough surface collector (PTSC) installed within a solar powered ship (SPS). For the current investigation, the non-Newtonian Maxwell type, as well as a porous medium and Darcy–Forchheimer effects, were used. The flow in PTSC was produced by a nonlinear stretching surface, and the Cattaneo–Christov approach was used to assess the thermal boundary layer’s heat flux. Similarity transformation approach has been employed to convert partial differential equations into solvable ordinary differential equations allied to boundary conditions. Partial differential and the boundary conditions have been reduced into a group of non-linear ordinary differential equations. A Keller-box scheme applied to solve approximate solutions of the ordinary differential equations. Single-walled carbon nanotubes -engine oil (SWCNT-EO) and Multiwalled carbon nanotubes/engine oil (MWCNT-EO) nanofluids have been utilized as working fluid. According to the findings, the magnetic parameter led to a reduction in the Nusselt number, as well as an increment in skin friction coefficient. Moreover, total entropy variance over the domain enhanced for flow rates through Reynolds number and viscosity fluctuations were monitored by using Brinkman number. Utilizing SWCNT-EO nanofluid increased the thermal efficiency between 1.6–14.9% in comparison to MWCNT-EO.

Onset about non-isothermal flow of Williamson liquid over exponential surface by computing numerical simulation in perspective of Cattaneo Christov heat flux theory

In view of increaing significance of non-isothermal flow of non-Newtonian fluids over exponential surfaces in numerous industrial and technological procedures such as film condensation, extrusion of plastic sheets, crystal growth, cooling process of metallic sheets, design of chemical processing equipment and various heat exchangers, and glass and polymer industries current disquisition is addressed. For comprehensive examination Williamson model expressing the attributes of shear thickening and thinning liquids is taken under consideration. The physical aspects of magnetic field applied in transverse direction to flow is also accounted. Heat transfer aspects are incorporated and analyzed by employing Cattaneo-Christov heat flux model. Mathematical formulation of problem is conceded in the form of PDE’s by implementing boudary layer approach and later on converted into ODE’s with the assistance of transformation procedure. The resulting equations are solved numerically using shooting and Runge–Kutta methods. Impact of involved parameters on flow distributions is displayed through graphs. From the analysis it is inferred that Cattaneo Christov heat flux law exhibits hyperbolic equation which follows the causality principle and make the problem more compatible to real world applications. It is also deduced that magnetic field suppresses the velocity field and associated boundary layer region. Decrease in temperature profile and heat transfer coefficient is found against inciting magnitude of thermal relaxation parameter. Substantial decrease in velocity is found against increasing magnitude of Williamson fluid parameter and magnetic field parameter whereas skin friction coefficient increments. Confirmation about present findings is executed by making comparison with existing literature.

Morphodynamics of Gully Development on the Platform–Slope System of Spoil Dumps under Platform Concentrated Flow

Severe gully erosion on spoil dumps, caused by dense concentrated flow derived from platforms, poses a significant threat to the land management of mining areas. However, little is known about the development processes and mechanisms of gullies on spoil dumps. A flow scouring experiment was conducted on an established platform–slope system under 3.6–5.04 m3 h−1. The soils of the system consisted of a surface sandy loam A layer and anunderlying clay loam B layer. The results showed that the platform exhibited a gully development process of headcut-incision–headcut-expansion–stabilization and the steep slope experienced gully development of A-layer incision–A-layer expansion–B-layer incision–stabilization. The results showed 88.97–100% of Froude Number (Fr) decrement and 47.90–88.97% of Darcy–Weisbach roughness coefficient increment finished in the two incision stages on the steep slope. Gully depth has the most sensitive response to flow hydraulics. A significant linear correlation exists between gully depth and shear stress, runoff power, Fr, and Reynolds Number (R2 > 0.337). Overall, the optimal hydraulic indicator varies within different stages for describing the gully morphology development, illustrating the different action mechanism between flow hydraulics and gully morphology. Our findings provide a theoretical support for future mechanistic studies of gully erosion and the land management on spoil dump.

Comparative Study of Dynamic Stall between an Aircraft Airfoil and a Wind Turbine Airfoil in an Air–Particle Flow

Dynamic stall in clean air flow has been well studied, but its exploration in air–particle (air–raindrop or air–sand) flow is still lacking. The aerodynamic performance loss of aircraft (NACA0012) and wind turbine (S809) airfoils and their differences during the hysteresis loop at different pitching parameters are also poorly understood. As shown in this paper, the reduced frequency has little effect on the value of the maximum lift coefficient increment caused by particles, but a larger one can enhance the hysteresis effect and drag the angle of attack, at which the maximum increment is obtained, from the up stroke to the down stroke. The large lift coefficient increments of two airfoils and their difference also have a similar change trend with the reduced frequency. Compared to that of NACA0012 airfoil, the increments of S809 airfoil are obviously greater at three mean angles of attack, especially at 8°, which is the commonly used operating angle. In addition, the angle of attack, at which the maximum lift coefficient is obtained, can be significantly changed by particles in two regions: one is under the effect of deep stall, the other is under the effect of light stall at a low, reduced frequency.

Flexoelectric-boosted piezoelectricity of BaTiO3@SrTiO3 core-shell nanostructure determined by multiscale simulations for flexible energy harvesters

Achieving lead-free piezoelectric nanoparticles with excellent electromechanical responses is in great demand for fabricating nanoscale electronic devices. Recently, the coupling effect of combining flexoelectricity and piezoelectricity has attracted attention as a promising approach to control electromechanical properties. However, the implication of the coupling for the nanoparticles in this regard has been challenging due to its difficulty in controlling and observing the internal strain gradient. In this study, we demonstrate the flexoelectric-boosted electromechanical properties of piezoelectric nanoparticles using an induced built-in strain gradient in heterogeneous core-shell nanostructure. The composition-graded core-shell structure of BaTiO3@SrTiO3 nanoparticles enables a significant increment of the effective piezoelectric charge coefficient via the chemical heterogeneities-induced lattice strain gradient. Through the combinations of ab-initio calculation and multiphysics simulations, the origin of the strain distribution over nanoparticles is theoretically interpreted with accompanying phase balance and diffusion criteria. In addition, our designed core-shell nanoparticles-based energy harvesting devices generate highly efficient and flexoelectric-boosted piezoelectric output signals. Individual core-shell nanoparticles and related elastomeric nanocomposites reported in this work represent state-of-the-art electromechanical properties compared to previously reported piezoelectric nanoparticles and composites. This study provides a new source of inspiration for achieving high-performance lead-free piezoelectric nanostructures, paving the way for developing nano-electromechanical applications.

Hybrid nanofluid flow over two different geometries with Cattaneo–Christov heat flux model and heat generation: A model with correlation coefficient and probable error

The authors scrutinize the steady, MHD flow of SiO2−MoS2/water hybrid nanofluid towards two different geometries i.e. a wedge and a cone. The Tiwari and Das model is implemented with a generalized–Fourier's model, popularized as Cattaneo-Christov heat flux model. Analysis of heat transfer also incorporates the effects of suction, heat generation and thermal radiation. To showcase the relationship between engineering quantities and pertinent parameters involved in the study, the correlation coefficient for heat transfer coefficient and the skin friction coefficient is computed followed by the computation of probable error and statistical declaration. Similarity transformations are utilized to remodel the constitutive laws of flow in non-dimensional form. Numerical computation of non-linear, coupled O.D.E.’s is performed with the support of the Runge-Kutta-Fehlberg scheme and shooting method. Graphical and tabular illustrations of computed results are provided to report the variation in flow properties with the fluctuation in physical parameters. In both cases, i.e. flow close to a wedge and a cone, the temperature of hybrid nanofluid enhances on intensifying the thermal radiation and experiences a decrement with thermal relaxation parameter and magnetic field. Rising values of the suction parameter, thermal relaxation parameter, and thermal radiation cause increment in heat transfer coefficient. Interestingly, it was spotted that the heat generation parameter has contrary effects on temperature distribution over the two geometries.

Multisalt chemistry in ion transport and interface of lithium metal polymer batteries

Solvent-free solid-state polymer electrolytes (SPE) that go beyond the barriers like intrinsic low ionic conductivity, slow ion dynamics, and unstable electrode-electrolyte interphase will be fundamental for realizing the next generation of safe and high-performance lithium metal batteries. Hereby, cross-linked solid polymer electrolyte (XSPE) networks based on multisalt chemistry are synthesized using photopolymerization reaction, which outshine the conventional single salt-based XSPEs. By introducing the multisalt chemistry, an enhanced Li+ ion transport (ionic conductivity and short residence time) via anion mediated transfer (AMT) and improved interfacial characteristics (e.g., stable Li|electrolyte interphase, smooth Li-deposition) are demonstrated. Furthermore, a three-times increase in Li+ ion transference number and nearly one order of magnitude increment in diffusion coefficient are achieved. Using theoretical calculations, we propose an AMT-based ion conduction pathway in multisalt-based XSPEs. Besides, the superior electrochemical performance of multisalt-based XSPEs compared to single salt-based polymer electrolytes in Li-metal polymer batteries (LMPB) using C-LiFePO4 and LiNi0.8Co0.15Al0.05O2 cathodes are successfully demonstrated.

Numerical investigation on thermal hydraulic performance of hybrid wavy channels in a supercritical CO2 precooler

Heat transfer enhancement within the precooler in supercritical CO2 Brayton cycles is challenging due to the dramatic variations of thermophysical properties. The local flow and heat transfer characteristics of a straight channel PCHE are analyzed firstly in this paper and the idea of thermophysical property-matching partitioned heat transfer enhancement is proposed accordingly. Subsequently, three types of hybrid channel, where sinusoidal wavy structures are combined with straight channel in different ways, are designed to examine the effectiveness of the partitioned heat transfer enhancement idea. A comparative study on the thermal hydraulic performance is performed with different geometrical parameters under different working conditions. The results indicate that the partitioned heat transfer enhancement shows great advantages in reducing the total pressure drop under the given heat flux boundary conditions. Compared to the full-wavy and the other two hybrid channels, the overall thermal hydraulic performance of the type-C channel is the best. A maximum pressure drop reduction of 23% could be observed in the type-C channel (with the wavy section used in the low-temperature region) compared to that in the type-A channel (with the wavy section used in the high-temperature region). Such advantage will become more prominent when the outlet temperature of the precooler is closer to the pseudocritical temperature. Moreover, the averaged increment of local heat transfer coefficient in the wavy section is 1.56 kW/m2⋅K for the type-C channel when compared to the straight channel section. It's also found that the effects of gravity on the local heat transfer coefficient are almost negligible in the high temperature region, while heat transfer in the low temperature region can be affected by changing the placing direction of the precooler. The present study may provide a practical guidance on the development of highly efficient heat exchangers where the thermophysical properties of the working fluid are highly variable.

Thermal and thermo‐hydraulic behaviour of alumina‐graphene hybrid nanofluid in minichannel heat sink: An experimental study

Thermal and pressure drop aspects of a minichannel heat sink have been investigated experimentally using distilled water as base fluid with alumina, graphene and alumina-graphene hybrid composition at 0.01% volume concentration. The reasons to select alumina-graphene as a potential nanomaterials combination for hybrid nanofluids are as: (i) thermal conductivity enhancement and (ii) to investigate the effect of morphology (shape and size of nanoparticles). Alumina (Al2O3) is oxide and has spherical shape whereas graphene is allotrope of carbon and has platelet shape. To examine the effect of different nanoparticles (in terms of shape, size and properties) dispersed hybrid nanofluid on hydrothermal bahaviour is an interesting study. Effects of Reynolds number (80-450), flow rate (0.1-0.5 L/min) and fluid inlet temperature (20-40°C) are studied. The effects of uniform heat flux of 50 and 66.7 W/cm2 on hydrothermal behaviour of a minichannel are also examined. The increment in convective heat transfer coefficient (HTC) is 30.93% at 30°C with graphene/water composition nanofluid than water base fluid. A penalty of 23.82% has been observed in pressure drop with graphene/water nanofluid over base fluid. As inlet temperature increases, Nusselt number (Nu) increases while adverse effect is found in case of friction factor. Performance evaluation criteria (PEC) has been observed more than 1 for all nanofluids and hybrid nanofluids, which ensured that nanofluids act as a better electronic cooling agent than water. Al2O3 + graphene hybrid nanofluid delivers optimum comparison factor (HTC to pressure drop ratio) and lower entropy generation rate among used working fluids. Graphene/water nanofluid yields less comparison factor compared to other working fluids irrespective of high HTC. h/Δp is favourable for nanofluid of unlike particles of hybrid composition (in terms of particle size, properties and shape) as compared to mono nanofluid and hybrid nanofluid having similar particles.

Magnetohydrodynamic Flow and Heat Transfer Over an Exponentially Stretching/Shrinking Sheet in Ferrofluids

In this research, the problem of magnetohydrodynamic flow and heat transfer over an exponentially stretching/shrinking sheet in ferrofluids is presented. The governing partial differential equations are transformed into nonlinear ordinary differential equations by applying suitable similarity transformations. These equations are then solved numerically using the shooting method for some pertinent parameters. For this research, the water-based ferrofluid is considered with three types of ferroparticles: magnetite, cobalt ferrite, and manganese-zinc ferrite. The numerical solutions on the skin friction coefficient, Nusselt number, velocity and temperature profiles influenced by the magnetic parameter, wall mass transfer parameter, stretching/shrinking parameter, and volume fraction of solid ferroparticle are graphically displayed and discussed in more details. The existences of dual solutions are noticeable for the stretching/shrinking case in a specific range of limit. For the first solution, an increasing number in magnetic and suction will also give an increment of skin friction coefficient and Nusselt number over stretching/shrinking sheet. For the skin friction coefficient only, it is showed a decreasing pattern after the intersection. Besides, the presence of ferroparticles in the fluids causes a high number of the fluid’s thermal conductivity and heat transfer rate.

Dose-Response Relationship Between Long-Term Blood Pressure Variability and Cognitive Decline.

We aimed to test whether higher long-term blood pressure variability was associated with accelerated rate of cognitive decline and evaluate potential dose-response relationship. Original survey data from the Health and Retirement Study and the English Longitudinal Study of Ageing were used. Standardized Z score of cognitive function was the main outcome measure. Visit-to-visit blood pressure SD, coefficient of variation, and variation independent of mean were used. Linear mixed model and restricted spline were applied to assess association and explore dose-response pattern. Segmented regression was used to analyze dose-response relationship and estimate turning point. Meta-analysis using random-effects model was conducted to pool results, with I2 used to test heterogeneity. A total of 12 298 dementia-free participants were included (mean age: 64.6±8.6 years). Significant association was observed between blood pressure variability and cognitive decline. Each 10% increment in coefficient of variation of systolic and diastolic blood pressure was associated with accelerated global cognitive decline of 0.026 SD/y (95% CI, 0.016–0.036, P<0.001) and 0.022 SD/y (95% CI, 0.017–0.027, P<0.001), respectively. Nonlinear dose-response relationship was found (P<0.001 for nonlinearity), with clear turning point observed (P<0.001 for change in slopes). Higher long-term blood pressure variability was associated with accelerated cognitive decline among general adults aged ≥50 years, with nonlinear dose-response relationship. Further randomized controlled trials are warranted to evaluate potential benefits of blood pressure variability-lowering strategies from a cognitive health perspective.

Errors of structural seismic responses caused by frequency filtering based on seismic wave synthesis

In order to meet the requirements of shake tables, frequency filtration of seismic input is usually performed before tests. Aiming to study the error of seismic analysis caused by filtering, the artificial seismic waves before and after filtering with four different waveforms were synthesized in this paper. Based on a spring-friction isolation system, the effects of filtering on seismic responses with various spring constants, friction coefficients and envelope functions were investigated. The results show that the maximum acceleration of the pure friction system is not affected by filtering while the error of maximum relative displacement caused by filtering can reach 60% and decreases with the increment of the friction coefficient. For the spring-friction system, the friction coefficient corresponding to a smaller structural seismic response is exactly the most unfavorable friction coefficient for filtering error and hence needs more attention during shaking table tests. Filtering errors based on different waveforms have the same tendency despite some slight differences owing to the different responses.

Analysis of Hiemenz flow of Reiner-Rivlin fluid over a stretching/shrinking sheet

PurposeThis paper aims to theoretically and numerically investigate the steady two-dimensional (2D) Hiemenz flow with heat transfer of Reiner-Rivlin fluid over a linearly stretching/shrinking sheet.Design/methodology/approachThe Navier–Stokes equations are transformed into self-similar equations using appropriate similarity transformations and then solved numerically by using shooting technique. A simple but effective mathematical analysis has been used to prove the existence of a solution for stretching case (λ> 0). Moreover, an attempt has been laid to carry the asymptotic solution behavior for large stretching. The obtained asymptotic solutions are compared with direct numerical solutions, and the comparison is quite remarkable.FindingsIt is observed that the self-similar equations exhibit dual solutions within the range [λc, −1] of shrinking parameter λ, where λc is the turning point from where the dual solutions bifurcate. Unique solution is found for all stretching case (λ > 0). It is noticed that the effects of cross-viscous parameter L and shrinking parameter λ on velocity and thermal fields show opposite character in the dual solution branches. Thus, a linear temporal stability analysis is performed to determine the basic feasible solution. The stability analysis is based on the sign of the smallest eigenvalue, where positive or negative sign leading to a stable or unstable solution. The stability analysis reveals that the first solution is stable that describes the main flow. Increase in cross-viscous parameter L resulting in a significant increment in skin friction coefficient, local Nusselt number and dual solutions domain.Originality/valueThis work’s originality is to examine the combined effects of cross-viscous parameter and stretching/shrinking parameter on skin friction coefficient, local Nusselt number, velocity and temperature profiles of Hiemenz flow over a stretching/shrinking sheet. Although many studies on viscous fluid and nanofluid have been investigated in this field, there are still limited discoveries on non-Newtonian fluids. The obtained results can be used as a benchmark for future studies of higher-grade non-Newtonian flows with several physical aspects. All the generated results are claimed to be novel and have not been published elsewhere.

Optimization of the Slotted Gurney-Flap geometry applied to NACA 0012 airfoil for aerodynamic performance improvement

The salient aim of this paper is the shape optimization of an airfoil equipped with Gurney-Flap for aerodynamic performance improvement. The optimization of the slotted Gurney-Flap for improving the aerodynamic efficiency and increasing the lift force of NACA 0012 is the novelty of this research. The Genetic Algorithm, Artificial Neural Network, and Computational Fluid Dynamics are employed for shape optimization. The optimization variables include the height and thickness of the GF; also, the thickness and position of the slot. All analyses have been conducted at Re=0.45×106 and AOA=8o to simulate the take-off phase. After validating numerical results, the optimization process was conducted with two different fitness functions of lift force and aerodynamic efficiency. According to the results, the geometry representing an optimized lift coefficient compared to the geometry with optimized aerodynamic efficiency has a considerably higher height. Furthermore, the thickness of the slot in the first geometry is lower than the second geometry. The first optimized geometry leads to a 21.64 percent lift coefficient increment; there is a 293 percent increment in aerodynamic efficiency due to the second optimized geometry. As a result, it can be indicated that the help of slotted optimized Gurney-Flap can provide the required lift force for Short Take-Off Landing distance.