Minimum Drag Research Articles

A trim problem formulation for maximum control authority using the Attainable Moment Set geometry

This paper presents a generic trim problem formulation, in the form of a constrained optimization problem, which employs forces and moments due to the aircraft control surfaces as decision variables. The geometry of the Attainable Moment Set (AMS), i.e. the set of all control forces and moments attainable by the control surfaces, is used to define linear equality and inequality constraints for the control forces decision variables. Trim control forces and moments are mapped to control surface deflections at every solver iteration through a linear programming formulation of the direct Control Allocation algorithm. The methodology is applied to an innovative box-wing aircraft configuration with redundant control surfaces, which can partially decouple lift and pitch control, and allow direct lift control. Novel trim applications are presented to maximize control authority about the lift and pitch axes, and a “balanced” control authority. The latter can be intended as equivalent to the classic concept of minimum control effort. Control authority is defined on the basis of control forces and moments, and interpreted geometrically as a distance within the AMS. Results show that the method is able to capitalize on the angle of attack or the throttle setting to obtain the control surfaces deflections which maximize control authority in the assigned direction. More conventional trim applications for minimum total drag and for assigned angle of elevation are also explored.

Development of the Low Toxic Cross Polar Air Transport using Innovative Hydrogen Projection for Large Aircraft and Airships

The new shortly and low cost Regular Airlines Cargo & PAX directions via Arctic Cross Polar Air Transportation Routes of the future High Ecology Efficiency and Safety ICAO Strategy will be base on the more perspective for Trans Continental Airlines Operations by IATA International Law Regulations and World Climate Protect Law. Using the more shortly directions of Trans Polar Flight for Long-Haul Aircrafts (LHA) Routes by leader Airlines Sky Teams with Aeroflot are request to find new Geometrical Layout of Aircraft Design Industrial Projections & Products Lines. The increase in the dimension of LHA came into conflict with modern Airport Infrastructure and led to the search for alternative Arctic Planes & Dirigibles Options for constructively layout circuit solutions with protection of minimum weight and drag issues in order to deal with this contradiction. Computer Digital Aircraft Structural-Parametric Analysis of the influence of Aviation Infrastructure Constraints in the basing of LHA on the choice of alternative Design Options for Lift Fuselage Body or Flying-V layout was carried out.

Experimental Validation and Evaluation of a Coupled Twist-Camber Morphing Wing Concept

A morphing wing concept allowing for coupled twist-camber shape adaptation is proposed. The design is based on an optimized thickness distribution both spanwise and chordwise to be able to morph the wing sections into targeted airfoil shapes. Simultaneously, the spanwise twist is affected by the actuation. The concept provides a higher degree of control on the lift distribution which can be used for roll control, drag minimization, and active load alleviation. Static deformation and flight tests have been performed to evaluate and quantify the performance of the proposed mechanism. The ground tests include mapped actuated wing shapes, and wing mass and actuation power requirements. Roll authority, load alleviation, and aerodynamic efficiency estimates for different configurations were calculated using a lifting line theory coupled with viscous 2D airfoil data. Roll authority was estimated to be low when compared to a general aviation aircraft while the load alleviation capability was found to be high. Differences between the lift to drag ratio between the reference and morphing wing configurations are considerable. Mass and actuation energy present challenges that can be mitigated. The flight tests were used to qualitatively assess the roll control capability of the prototype, which was found to be adequate.

Magnetohydrodynamics radiative dissipative slip flow of hydrogen-oxide (H2O) infused with various shape tungsten, tin, titanium (nanometer) particles over a nonlinear radial stretching surface

Optimal control over heat transfer during the manufacturing of various significant cylindrical components is vital to achieving a desirable finished product. Insertion of various-shaped nanoparticles provides a promising solution to the problem at hand due to their greater thermal conductivity and unique features. Keeping in view, the present article is an effort to explore the slip flow of hydrogen-oxide [Formula: see text] infused with lamina- and column-shaped tungsten, tin, and titanium nanometer-sized particles over a nonlinear radially stretching surface. The physical model is presented by utilizing the fundamental laws of mass, momentum, and energy conservation. Magnetohydrodynamics, thermal radiation, and viscous dissipation effects are incorporated to provide physically realistic analysis. Utilizing scaling analysis flow governing problem is converted into a set of higher-order nonlinear Ordinary differential equation’s which afterward are tackled numerically. Quantities of practical significance such as surface friction and heat flux are portrayed through bar graphs and are examined physically in a detailed manner. Column shape tungsten nanoparticles offered minimum surface drag with the highest heat transfer rate compared to the other two particles making them an optimal choice in manufacturing cylindrical components as per our study.

Self-deployable drag sail folded nine times

• Folding method for 9 folds of the Highly Flexible Frames and the ability to deploy. • Experiments with the HFF in the pocket reviled the need for heat treating the steel. • Uncoiling of the HFF accrued, this was redeemed with a tight pocket depth. Increased focus on space debris push regulations by the UN and thereby the demand for debris removal systems to be implemented in future spacecraft. This research focuses on debris removal of post-mission satellites in LEO using drag augmented deorbit into the earth's atmosphere. By using gossamer sails (drag sails), aerodynamic breaking can effectively be achieved in LEO up to 700 km. The presented work supplements the research performed in the H2020 project Technologies for Self-Removal of Spacecraft (TeSeR), in which the Self-Deployable Deorbiting Space Structure (SDSS) has been further developed. It is devised how to obtain a self-deployable drag sail folded nine times for use in debris removal for a 6U CubeSat, i.e. an SDSS/9. Achieving nine folds of Highly Flexible Frame (HFF) is essential to maximize the drag sail area when it is unfolded and hereby increasing drag force. The nine times folded HFF has been modeled in computer simulations and demonstrated in a lab. From lab-based research, several issues have been identified when folding the HFF nine times. Of these, two main issues are addressed in this paper, i.e. relaxation and uncoiling. When folded nine times, the von Mises stresses computed by FEM reach 1857 MPa. Combined with residual stresses, this is causing yield and relaxation in the HFF and reducing the deployability. A minimum drag sail diameter is identified for this setup, and the high-strength stainless steel should be heat treated to relieve residual stresses before folding. A side-mounted design is chosen for the configuration of the SDSS. This reduces friction during the release and deployment of the drag sail. From thorough testing, it is observed that the uncoiling of the HFF during storage in the pocket significantly reduces the deployability of the SDSS. To mitigate both radial and axial uncoiling of the HFF in the pocket, the pocket diameter and height should be designed with an exact fit to the folded diameter and height of the ideally folded HFF with the drag sail included. Based on this research, a new design of the SDSS/9 for CubeSats is devised, and preliminary testing indicates good consistencies more test is necessary to determine the reliability of the side mounted SDSS. Hence, from the research, it is concluded that SDSS/9 is a feasible solution for a low-cost add-on debris removal system. Furthermore, the side-mounted design allows integration with additional collision protection of the spacecraft.

CFD Analysis on the Effect of the Change in Profile Geometry on Drag Reduction of a Sedan Car

This study is a 3-dimensional CFD analysis of external aerodynamics of a generic car model. The aim of this study was to visualize the flow field and examine the effect of modification of some geometrical parameter on the drag coefficient of the car body. The reduction in drag allows the vehicle to operate at lower fuel consumption which eventually results in fuel economy and lower pollution. Also artificially guided air maintains stability of vehicles. Therefore, flow field analysis is important for aerodynamic analysis of a car body. The results obtained is compared and validated with existing experimental data and found to be deviated by 5.5%. The two specific name of geometrical parameter for this study which is modified are front bumper angle and hood radius. The three angles are taken into consideration for front bumper angle as 10-degree, 15-degree and 20-degree and at each front bumper angle three hood fillet radius are 200mm, 250mm and 300 mm respectively. It is found in the study that increasing the angle of inclination of front bumper angle decrease the drag coefficient and also increasing the hood fillet radius decreases the drag coefficient. The minimum drag coefficient in the study is found to be 0.3939 at front bumper angle 15 degree and hood fillet radius 300mm. The maximum reduction of the drag coefficient from the base case in which both the parameter is kept at zero-degree angle and zero fillet radius is 6.50%. The flow field suggested that as we increase the inclination angle the frontal projected area is reduced locally and pressure drag is reduced and also giving the fillet at corner the air flow is guided smoothly which also results in reduced drag.

Numerical investigations on the flow control over bumped surface circular cylinders

External flow-induced forces on bumped surface circular cylinders in laminar flow regimes are studied at a range of Reynolds numbers up to 200. This study examines three types of bumped surface cylinders, including square, triangular, and dimpled surfaces. The bumped surfaces are set at the top surface of the cylinder. The bumps are arranged between θ = 0° and 90° from the front stagnation point of the cylinder. It is shown that the presence of a bump on the leading edge of the cylinder manipulates the vortex dynamics and leads to significant changes in flow-induced forces. The results show that due to asymmetrical imposed pressure on the cylinder, the generated negative vorticity of the square bumped surface is approximately 28% stronger than those of triangular and dimpled surfaces once θ = 90°. Comparing to a smooth cylinder, significant reductions in drag and lift coefficients are obtained at Re = 150 once a bump is created on the surface of the cylinder apart from the type of geometry. It is found that the maximum time-mean lift coefficient is produced once the bump is located at θ≥ 45°. Furthermore, the minimum drag force is generated for the bumped surface cylinder with θ = 0° and Re = 150.

Modelling of Drag Force Reduction for a Waterjet Propulsion System

Abstract The paper provides simulation results for SUP (Stand Up Paddle) board appendage resistance. Additional propulsion is added to the SUP board. It is equipped with a waterjet. The waterjet is attached to the board rudder. This increases the drag coefficient for rudder five times. To reduce the drag variable, design options for the waterjet duct were proposed. The simulation tests were performed using SolidWorks Flow software using two types of simulations, namely, the pressure on the body and the flow around the body. The objective was to streamline the bluff duct of the waterjet and thus to create the appendage design with minimum drag force from fluid flow and possibly greater Inlet Velocity Ratio. Calculations showed that rounding-off the edges of waterjet duct resulted in 35 % of drag coefficient reduction, while further streamlining reduced it by additional 10 %.

Coupled Boundary-Layer Suction and Airfoil Optimization for Hybrid Laminar Flow Control

The present work incorporates the effects of boundary-layer suction in designing airfoils for hybrid laminar flow control application. The overall airfoil shape, the suction velocity distribution, and its location are optimized for minimum total drag while sustaining laminar flow over 80% of the airfoil top surface. Nondominated Sorting Genetic Algorithm II is used with the aerodynamic load computations from XFOILSUC and transition prediction from the improved Van Ingen method. The airfoil is designed for short-range subsonic conditions for three design lift-coefficient scenarios: 1) 0.4, 2) in the range of 0.3–0.7, and 3) in the range of 0.3–0.7 with suction onset at midchord. The optimized airfoil for scenario 3, with suction onset at midchord, results in a thicker airfoil with natural laminar flow (NLF) on the upper surface comparable to NLF airfoils. The total drag reduces by one-third due to the effects of suction. On the other hand, without limiting the suction onset (scenario 2), a thinner airfoil with longer NLF on the bottom surface and lower total drag is obtained. Optimum suction onset location is predicted to be at 30% of the chord. Suction is also observed to improve the drag bucket at off-design conditions.

Hull form optimization based on calm-water wave drag with or without generating bulbous bow

In the ship design process, hull form design and optimization play an important role. In the research and engineering fields of hull form optimization, the resistance performance is most noticed among all the hydrodynamic performances. In this paper, we focus on the calm-water drag optimization for a high-speed slender hull without a bulbous bow, and the generation of the bulbous bow is introduced in detail, such as the hull form deformation methods and the knot-insertion procedure for the NURBS surface. Two optimization cases are given. In case 1, only shifting method is used, while in case 2, shifting and Radial Basis Function (RBF) methods are both used. During the hydrodynamic evaluation of the new sample hulls, the potential flow solver is applied, and the verification and validation procedure is done at first. The genetic algorithm is used to obtain two optimal ships with minimum wave drag. Optimization results show that even when we do not generate a bulbous bow, the optimal hull will have a relatively big decrease of the wave drag coefficient. However, favorable interference of the wave systems conducted by the generated bulbous bow can help reduce the wave drag coefficient to a greater extent, showing that the bulbous bow generation method proposed in this paper has potentials in the resistance optimization of the medium- or high-speed ship hulls.

Adjoint-based aerodynamic drag minimisation with trim penalty

AbstractThe aerodynamic performance of conventional aircraft configurations are mainly affected by the wing and horizontal tail. Drag reduction by shape optimisation of the wing, while taking into account the aircraft trimmed constraint, has more benefit than focusing solely on the wing. So in order to evaluate this approach, the following study presents results of a single and multipoint aerodynamic shape optimisation of the wing-body-tail configuration, defined by the Aerodynamic Design Discussion Group (ADODG). Most of the aerodynamic shape optimisation problems published in the last years are focused mainly on the wing as the main driver for performance improvement, with no trim constraint and/or excess drag obtained from the fuselage, fins or other parts. This work partially fills this gap by an investigation of RANS-based aerodynamic optimisation for transonic trimmed flight. Mesh warping and geometry parametrisation is accomplished by fitting the multi-block structured grid to a B-spline volumes and performing the mesh movement by using surface control points embedded within the free-form deformation (FFD) volumes. A gradient-based optimisation algorithm is used with an adjoint method in order to compute the derivatives of the objective and constraint functions with respect to the design variables. In this work the aerodynamic shape optimisation of the CRM wing-body-tail configuration is investigated, including a trim constraint that is satisfied by rotating the horizontal tail. The shape optimisation is driven by 432 design variables that envelope the wing surface, and 120 shape variables for the tail, as well as the angle of attack and tail rotation angles. The constraints are the lift coefficient, wing’s thickness controlled by 1,000 control points, and the wing’s volume. For the untrimmed configuration the drag coefficient is reduced by 5.76%. Optimising the wing with a trim condition by tail rotation results in shock-free design with a considerably improved drag, even better than the untrimmed-optimised case. The second optimisation problem studied is a single and multi-point lift constraint drag minimisation of a gliding configuration wing in transonic viscous flow. The shock is eliminated, reducing the drag of the untrimmed configuration by more than 60%, using 192 design variables. Further robustness is achieved through a multi-point optimisation with more than 45% drag reduction.

Assessment of physical and aerodynamic properties of corn kernel (KSC 704)

AbstractPhysical and aerodynamic properties of agricultural products have been used to precision design of the machinery and different postharvest operations. In this study, some physical and aerodynamic properties of corn kernels were investigated as a function of size at three levels of small, medium, and large (8.41 mm, 9.60 mm, and 11.62 mm, respectively) and moisture content in the range of 10 to 25% (wet basis). According to results, with increasing the moisture content from 10 to 25%, the length; width; thickness; geometric mean diameter; mass; and volume of the small, medium, and large kernels linearly increased by 2.22%, 2.40%, and 1.68%; 3.76%, 1.82%, and 1.55%; 3.98%, 2.49%, and 2.67%; 3.29%, 2.23%, and 1.93%; 8.44%, 7.38%, and 8.12%; and 11.32%, 10.71%, and 10.21%, respectively. In this regard, the projection area of the specimens increased nonlinearly by 6.06%, 4.26%, and 3.26%, respectively; whereas, true density decreased nonlinearly by 2.65%, 2.91%, and 1.90%, respectively. The maximum terminal velocity (12.41 m/s) and Reynolds number (6,037.44) were observed in large kernels and the moisture content of 25%; whereas, the minimum terminal velocity (8.32 m/s) and Reynolds number (3,016.55) were observed in small kernels and the moisture content of 10%. Maximum and minimum drag coefficients (1.014 vs. 0.302) were observed in small kernels at the moisture of 10% and large kernels at the moisture of 25%, respectively. The polynomial model was chosen as a suitable model in order to foretell the terminal velocity, Reynolds number, and drag coefficient of kernels as a function of moisture content and size.Practical ApplicationsMechanical damages to seeds at harvesting, transporting, and threshing are major concerns for farmers and farming experts. All the processes of wind transfer, flotation, and seed removal from seed mixture and the stalks and husks depend on the behavior of the seeds in the wind flow. Therefore, it is crucial to determine the physical and aerodynamic properties of various crops to analyzing their behavior during transport, processing, and precise design of farm equipment and machines to minimize wastes.

Computational and Experimental Study for Reducing Forebody Wake Effect by Proper Designing of a Slit cut Square Parachute used for Sonobuoy Drop

This paper discusses the design of a square parachute based on classical approach, computational analysis and experimentation. This parachute will be used to drop directional sonobuoy on the sea to locate and classify the submarines. Design improvements are brought out by providing slits into a solid square canopy of parachute to bring in more stability and minimum drift during descend. Specifically, the effect of upstream sonobuoy, RANS model, suspension line length, canopy size and slit size in flow structure were considered. The predicted drag coefficients obtained from CFD for square canopy with slit-cuts compared with the results of wind tunnel experiment and found that the increase in the suspension-line length and/or of the surface area of the parachute canopy helps in better stability and results in the minimum drag loss.

Improvement of Upland Rice Variety by Pyramiding Drought Tolerance QTL with Two Major Blast Resistance Genes for Sustainable Rice Production

Varalu is an early maturing rice variety widely grown in the rainfed ecosystem preferred for its grain type and cooking quality. However, the yield of Varalu is substantially low since it is being affected by reproductive drought stress along with the blast disease. The genetic improvement of Varalu was done by introgressing a major yield QTL, qDTY12.1, along with two major blast resistance genes i.e. Pi54 and Pi1 through marker-assisted backcross breeding. Both traits were transferred till BC2 generation and intercrossing was followed to pyramid the two traits. Stringent foreground selection was carried out using linked markers as well as peak markers (RM28099, RM28130, RM511 and RM28163) for the targeted QTL (qDTY12.1), RM206 for Pi54 and RM224 for Pi1. Extensive background selection was done using genome-wide SSR markers. Six best lines (MSM-36, MSM-49, MSM-53, MSM-57, MSM-60 and MSM-63) having qDTY12.1 and two blast resistance genes in homozygous condition with recurrent parent genome of 95.0%-96.5% having minimal linkage drag of about 0.1 to 0.7 Mb were identified. These lines showed yield advantage under drought stress as well as irrigated conditions. MSM-36 showed better performance in the national coordinated trials conducted across India, which indicated that improved lines of Varalu expected to replace Varalu and may have an important role in sustaining rice production. The present study demonstrated the successful marker-assisted pyramiding strategy for introgression of genes/QTLs conferring biotic stress resistance and yield under abiotic stress in rice.

Aerodynamic Design Optimization of a Transonic Strut-Braced-Wing Regional Aircraft

The aerodynamic design and fuel burn performance of a Mach-0.78 strut-braced-wing regional jet is investigated through aerodynamic shape optimization based on the Reynolds-averaged Navier–Stokes equations. Conceptual-level multidisciplinary design optimization is first performed to size the strut-braced-wing aircraft for a design mission similar to the Embraer E190-E2, with a design range of 3100 nmi at a maximum capacity of 104 passengers, and a maximum payload of 30,200 lb. For direct performance comparisons, a conventional tube-and-wing regional jet is also sized and optimized based on the same reference aircraft. Gradient-based aerodynamic shape optimization is then performed on wing–body–tail models of each aircraft, with the objective of drag minimization at cruise over a 500 nmi nominal mission. Design variables include twist and section shape degrees of freedom, which are realized through a free-form and axial deformation geometry control system, whereas nonlinear constraints include constant lift, zero pitching moment, minimum wing volume, and minimum maximum thickness-to-chord ratios. Results indicate that the optimizer is capable of mitigating shock formation, boundary-layer separation, and other flow interference effects from each wing design, including those within the wing–strut junction of the strut-braced wing. With year 2020 technology levels, the strut-braced-wing regional jet offers a 12.9% improvement in cruise lift-to-drag ratio over an Embraer E190-E2-like conventional tube-and-wing aircraft, which translates to a 7.6% reduction in block fuel for the nominal mission.

Black-Box Function Aerodynamic Topology Optimization Algorithm via Machine Learning Technologies

The objective of this research is to construct an efficient global topology optimization method using machine learning technologies. In the conventional design process of mechanical design, the conceptual design is the earliest stage of the design process; and it is carried out based on the designer’s own idea/experience. Therefore, it is difficult to obtain innovative and high-quality concepts overwhelming the designer’s knowledge since the earliest stage of the design process has the largest impact. In this research, therefore, the black-box function aerodynamic topology optimization algorithm via machine learning technologies (FANTOM) is developed to overcome the problem. In the FANTOM approach, topology optimization problems are solved using/combining two efficient global optimization methods developed by the authors: the efficient global optimization method for discontinuous optimization problems with infeasible regions using classification method, and the efficient global optimization method via clustering/classification methods and exploration strategy. In the present approach, topological optimal designs can be obtained only by setting an objective function and constraint conditions. The validity of the FANTOM approach is demonstrated in an inviscid drag minimization problem at a two-dimensional supersonic flow condition, which provides an optimal topology as the Busemann biplane airfoil. Executing topology optimizations with the variation in freestream Mach number, it is also demonstrated that the FANTOM approach can explore topological optimal designs robustly.

Use of a force measuring walker to optimize recovery after median sternotomy

Abstract Funding Acknowledgements Type of funding sources: None. BACKGROUND Patients often need to use their arms to assist with functional activities, but after open-heart surgery, pushing with the arms is often limited to <10 lb (4.5 kg), to minimize force across the healing sternum. Restricting arm use often limits patient functional independence which can contribute to longer hospital stays and greater need for care after hospitalization. Therefore, appropriate arm use is important for return to function. Currently, no method exists to measure patient upper extremity weight bearing (UEWB) forces objectively in clinical settings. The ultimate goal was to develop a walker that provides UEWB force feedback to patients recovering from median sternotomy. This research project included three interrelated parts that sequentially built on each other. PART 1 First, I conducted a secondary data analysis comparing UEWB force and Pectoralis Major Muscle EMG during functional mobility in younger vs. older subjects (n = 65). Results showed that the mean arm force was >10 lb before feedback training during all functional mobility tasks for both groups. There were significant differences in UEWB force and EMG between groups (young vs. old) and trials (pre- vs. post-feedback training). There was significantly greater improvement (change) in the UEWB force in the older than younger subjects. We also found a significantly greater reduction in EMG activity in the older subjects than younger subjects for all tasks except during stand-to-sit. Results suggested that patients, particularly older ones, may not accurately estimate UEWB force <10 lb, and feedback training is effective for improving accuracy. This established proof-of-concept, the need for a Clinical Force Measuring (CFM) walker, and the efficacy of its use with feedback training. PART 2 Next, I completed a qualitative study to obtain critiques of a CFM walker prototype from rehabilitation professionals through structured interviews that were recorded and transcribed. I coded key statements and phrases that allowed "themes" to emerge (Table 1), which guided device revisions. PART 3 Lastly, I fabricated and tested a second CFM Walker prototype (Figure 1) based on key design elements including: 1) integrated vertical force measuring capability, 2) ergonomic handles, 3) simple visual and auditory feedback with upper limit alarms, 4) streamline, stable, and manoeuvrable frame, 5) lightweight construction, 6) minimal drag, 7) adjustable height, 8) ability to disinfect, and 9) affordable cost. CONCLUSIONS The CFM Walker could help patients recover safer and faster from open heart surgery, especially elderly adults.

Study of wind loading and flow characteristics on an array of parabolic trough collectors

Wind loads and structure of the flow field around an array of parabolic trough collectors (PTCs) were investigated using Delayed Detached Eddy Simulation (DDES) method. A scaled three-dimensional (3D) model was adopted and simulated using the ANSYS-Fluent software. Several pitch angles, including θ = 0°, 45°, 135°, and 180° and the stow mode with the pitch angle, θ = 90°, and flow Reynolds number of 2×105, are considered for numerical solutions. For validation of the numerical model, the mean wind load coefficient on a stand-alone PTC and an array model of PTCs were simulated and compared with the wind tunnel data. Detailed analysis of wind characteristics and wind loading on an array for five-pitch angles was provided. Results demonstrated that except for the stow mode, the first PTC in the array experienced the maximum mean pressure in the upwind side of the PTCs model and corresponded to the maximum mean drag coefficient. Besides, the minimum mean drag coefficient belongs to the second row in the array except for the stow mode. A comparison between flow patterns around the PTCs revealed the high vorticity concentration in front of the collectors for pitch angles θ = 0° and θ = 180°.

Aerodynamic Characteristics of a Straight Wing with a Spiroid Wingtip Device

Abstract Spiroid wingtip devices (WD) offer a promising way of improving the lift drag ratio of UAVs, but may on the other hand lead to negative aerodynamic interference of the wing with the WD and deterioration of the aerodynamic characteristics as compared to a wing without the WD. Determining the influence of the geometric parameters of a spiroid WD on aerodynamic wing characteristics, however, remains an understudied field. In our study, we investigated the influence of the following geometrical parameters on wing aerodynamic characteristics with WD: area, radius, camber angle, constriction, and pitch of the spiroid. We found that the positive effect of the WD is present at a relative radius > 0.05, as well as with an increase in the lift coefficient C L as a result of an increase in the proportion of inductive resistance. For example, with the Reynolds number Re = 2.1×105 for a rectangular wing with an aspect ratio θ = 5.12 equipped with a spiroid WD with =0.15 the quality gain is almost 10% at C L = 0.5, and at C L = 0.7 is almost 20% and at C L = 0.7 – almost 20% compared to a wing without WD. Moreover, we found that a change in the camber angle WD θ provides an increase in the derivative of the lift coefficient with respect to the angle of attack in the range from θ = 0° to θ = 130°. By changing the camber angle, it is possible to increase the lift drag ratio of the layout up to 7.5% at θ = 90° compared to θ = 0° at the Reynolds number Re = 2.1×105. From the point of view of ensuring maximum lift drag ratio and minimum inductive drag, the angle θ = 90° is the most beneficial.

Numerical investigation of minimum drag profiles in laminar flow using deep learning surrogates

Abstract