Wing In Ground Research Articles

Revolutionizing Wing-in-Ground Effect: Investigating Structural Rigidity

The Wing-in-ground (WIG) effect aircraft utilize the ground effect to maintain flight above water or another surface while minimizing continuous contact with the ground. The propulsion of this aircraft primarily relies on the aerodynamic lift generated by specially designed wings, hulls, or other components that harness the ground effect phenomenon. The problem statement that occurs once conventional boats fail to successfully carry out the mission of intercepting intruders trespassing on national waterways. Due to inherent constraints in watercraft technical standards, existing watercraft technology lacks the power to pursue intruders to their full extent. To further improve the WIG craft operation, we propose enhancing its performance by using materials with better mechanical qualities and optimizing the construction to lower its overall size. These enhancements aim to bolster the WIG craft's capabilities and enable more efficient and effective interception of intruders in water environments. This research aims to investigate structural material qualities suited for WIG effect application and structural rigidity characteristics, with a particular focus on the joining model. In order to accomplish these objectives, the study utilizes Solidworks simulation to replicate the WIG craft model. The static simulation involves testing four different parameters: Models A, B, C, and D. The key focus during the model simulation is varying the types of connections used. The simulation data is then examined to estimate the strength of the material structure. The material applied to the WIG craft structure is S-glass fiber and 6061 aluminum alloy. Model D produced acceptable values for the least maximum stress, strain, and resultant displacement, among other models. The maximum stress value of Model D is 1,601 MPa, which does not exceed the tensile strength of the material. For the rigidity analysis in operating conditions, the Solidworks flow simulation is conducted. The manipulated variable for flow simulation is the velocity of airflow. The velocities conducted are 60 km/h, 90 km/h, 120 km/h, 15 km/h and 180 km/h. The flow simulation shows the maximum total pressure exerted on the structure, where the highest velocity produced is 103433 Pa. From both static and airflow simulation, it was concluded that the WIG craft model has good rigidity in terms of withstanding the external load and airflow pressure during the cruising conditions proposed.

Investigation of Lifting Force Affected by the Velocity and Angle of Attack (AoA) In Wing-in-Ground (WiG) Craft

The Wing-in-Ground (WIG) craft represents a pioneering vehicular innovation that exploits aerodynamic lift via a cushioning mechanism, enabling it to remain suspended above the water's surface. A notable concern encountered during the navigational manoeuvres of the WIG craft over the uneven sea terrain pertains to its potential impact on fuel efficiency during flight durations. This research objective is focused on the pivotal of ascertaining the optimal lifting force prerequisites for a prototype WIG craft. This comprehensive study entails an exploration of diverse combinations of velocities and angles of attack (AoA) to identify the most suitable configuration capable of attaining the requisite lift force levels. The study's methodology revolves around the adaptation of the actual WIG concept, encompassing a focus on the aerofoil profile and leveraging insights garnered from a design concept pertaining to WIG craft. To emulate real-world scenarios with precision, computational simulations employing the flow simulation capabilities of SolidWorks software are executed concurrently with the validation of a fabricated prototype. Parameters encompassing, angle of attack, and velocity are meticulously configured, adhering to the commonly employed parameters within the realm of WIG craft operations. The resulting outcomes are rigorously validated and subsequently compared against a lift coefficient of 1.25 at an angle of attack set at 16°, consistent with outcomes from prior research activities. This established angle of attack serves as a foundational reference for the present study's empirical conclusions. The culmination of these simulations yields the identification of an optimal arrangement characterized by a velocity of 120 km/h coupled with an angle of attack measuring 20°. This particular configuration consistently stimulates the requisite magnitude of lift force, thereby demonstrating the feasibility of elevating the WIG craft prototype without compromising stability or safety.

A fuel-efficient pathfinding algorithm for next-generation WIG crafts

ABSTRACT Wing-In-Ground (WIG) crafts have the advantage of being fuel-efficient by utilising the ground effect. Next-generation WIG crafts can choose flight paths that navigate over obstacles while flying at specific altitudes. However, current route computation algorithms for ships fail to account for paths that allow ships to navigate over obstacles. Leveraging fundamental path-finding approaches such as A* and Jump Point Search (JPS), our algorithms are designed to forecast routes that significantly improve operational efficiency. Validation was performed using real topographic data from Indonesia, focusing on fuel consumption metrics to evaluate the algorithms’ effectiveness. The results evaluate the superiority of our methods in optimising route selection for WIG crafts, marking a advancement in autonomous marine navigation technology.

Hydrodynamic characteristics of wing-in-ground effect oscillating hydrofoil on power extraction performance

The energy contained in the tidal motion of the seas and oceans has the potential to be a significant source of renewable energy. The oscillating hydrofoil current-energy turbine has a good performance to extract energy from the coupling of its heaving and pitching motions. In the present study, the wing-in-ground (WIG) effect has been considered to improve the power-extraction performance of the oscillating hydrofoils. The overset grid in the commercial computational fluid dynamic (CFD) software STAR CCM+ is applied to study the flapping hydrofoil with dynamic WIG effect between two hydrofoils. The simulation results show that the WIG effect can greatly improve the power extraction performance of the flapping hydrofoil. The WIG effect is asymmetric over the course of the foil moving toward or leaving from the symmetry plane. The distance of the gap has a major influence on the hydrodynamic performances of the flapping hydrofoil. For a moderate gap, the positive pressure on the lower surface enhances as the hydrofoil departs from the symmetry plane and causes an improvement of lift and moment coefficients. As the gap decreases further, the increasing negative pressure between the leading edge and the symmetry plane plays an essential role improving the power extraction as the hydrofoil approaches the symmetry plane. Compared to the case without the WIG effect, the power-extraction efficiency has an increment of 16.34% in the present study.

Investigating Planar and Nonplanar Wing Planform Optimisation for Ground Effect Aircraft

Wing-in-Ground (WIG) effect aircraft are gaining attention for their potential in reducing environmental impact. However, optimising wing planforms based solely on aerodynamics might improve performance while compromising static height stability of WIG aircraft. This study investigates the effects of planar and nonplanar wing planform optimisation for regional transport ground effect aircraft. Three distinct multiobjective wing planform optimisations are explored: planar wing optimisation, nonplanar wing optimisation, and nonplanar wingtip optimisation. These optimisations assess the impact on both aerodynamic efficiency and static height stability characteristics of a wing planform in ground effect, at three different flying altitudes. In extreme ground effect, the Pareto set includes wings with negative spanwise camber, enhancing both cushion sensation and aerodynamic efficiency by effectively utilizing ground effect, thus proving advantageous over planar wing configurations.

SIMULASI NUMERIK KARAKTERISTIK AERODINAMIKA PADA AIRFOIL NACA 4415 DENGAN MEMPERTIMBANGKAN GROUND EFFECT

Ground effect phenomenon is found when the lift-device such as wing, is placed near the ground. This phenomenon influences the aerodynamics characteristic whereby its appearance is important to be investigated. This work aims to study the influence of ground effect towards aerodynamics characteristion on the NACA4415 airfoil by varying the airfoil’s angle of attack (AoA) as well as the height of ground proximity. Numerical approach conducted on Fluent was carried out while steady assumption, moving wall boundary, and Spalart-Allmaras turbulence model were utilized. The outcomes were aerodynamics characteristic represented by lift and drag coefficients. The results showed that maximum was 1.736 on AoA 15o while maximum was 0.0108 on AoA 18o respectively. It also found that ground proximity also was affecting the values of and . On the height of 0.05 chord, maximum characteristic of lift was obtained while maximum drag was on the 0.8 chord at AoA 18o. It caused by airflow underneath the airfoil was faster due to the ground effect revaling the nozzle-effect, therefore the pressure was higher as according to the Bernoulli’s formulation. On the other hand, drag was related to the vortex generation in which AoA more influental than that of height. This work is hopefully beneficial as initial reference on the Wing-in-Ground (WIG) craft design, in particular on the airfoil selection.

Numerical study of a semi-passive oscillating hydrofoil on power-extraction with wing-in-ground effect

The performance of a semi-passive oscillating hydrofoil, with activated pitching motion and induced heaving motion, is numerically studied by OpenFoam. The two-dimensional incompressible Navier–Stokes equations are solved using a finite-volume numerical method coupling with an overset grid technique. First, the fluid–structure interaction problem involved in the dynamics of an oscillating hydrofoil with an energy harvesting system is examined. The two-dimensional analysis allows us to simulate dynamics of oscillating hydrofoil system over a large range of parameters for identifying the optimal areas for power extraction. A maximum efficiency of η=39.90% is achieved with an optimal set of parameters. The efficiency stays at a relatively high level with little variation in a large range of damping coefficient, providing a flexible selection for designers in practical applications. Thereafter, we concentrate on the wing-in-ground (WIG) effect, which has been reported as a great potential to improve the power extraction for oscillating hydrofoils. When the hydrofoil approaches the ground, a Venturi channel can be formed between the hydrofoil and the ground, which leads to a good timing of vortex–foil interactions. Benefit from the WIG effect, the amount of power extraction has a significant increase.

수면비행선박 착수 조건에 대한 CFD-MBD 연성해석 및 운항시험 결과 비교

In this study, 2-way coupled computational fluid dynamics (CFD) and multi-body dynamics (MBD) analysis has been performed for the water-landing condition of a wing-in-ground (WIG) effect ship model. Unsteady multi-phase fluid dynamic analysis based on Navier-Stokes equations and Lagrangian approach is performed adopting overset mesh technique in order to effectively simulate the dynamic behavior of a WIG ship. Actual flight test data for a typical water-landing condition provided by the WIG ship manufacturing company are well compared with results by the present numerical approach. It is shown that a high-fidelity numerical model can accurately predict the dynamic behavior of a WIG ship even considering the mutual effect of air and sea-water. Using the proposed numerical approach, time-dependent load variation imposed on each section of hull bottom surface as well as water landing performance of a WIG ship can be accurately analyzed and investigated in detail.

Aeroacoustic characteristics of multi-directional wing under the wing-in-ground effect

Characteristics of the generation and propagation of aerodynamic noise are unique to conventional ground vehicles or aircraft due to the wing-in-ground (WIG) phenomenon. This study numerically examines the aeroacoustic characteristics of a multi-directional wing under the WIG effect with different values of clearance. The flow field was simulated by using a large eddy simulation for six groups of wings with different clearances and one group of wings in free space, at a freestream velocity of 0.3 Ma and an angle of attack of 5°. Acoustic simulations were carried out for each condition by using Möhring's analogy, and the acoustic analysis was based on details of the flow field. A multi-vortex system was generated at the trailing edge of the wing when the clearance was lower than 0.2 C. It consisted of an oscillating attached vortex that expanded and shrank with continuous changes in energy, and two periodically shedding vortices were formed that generated a strong wall-bound vortex street downstream of the wing after shedding. An analytical approach was used to simultaneously analyze different dominant frequencies in each region of the sound field. We conclude that different intensities of the WIG effect led to remarkable differences in the characteristic frequency of aerodynamic noise induced by the multi-directional wing. The characteristic frequencies of aerodynamic noise of the multi-directional wing with a low clearance (clearance ≤ 0.2 C) were mainly caused by the wall-bound vortex street while those at a high clearance (clearance ≥ 0.4 C) were mainly caused by vortices on the wingtip.

Wing-in-ground craft longitudinal modeling and simulation based on a moving wavy ground test

Compared with the static wavy ground tests and moving flat ground tests, the moving wavy ground test eliminates the effect of the boundary layer and generates more accurate test results of the aerodynamics in the wave environment. This paper introduces a wind tunnel test of a wing-in-ground (WIG) effect craft with moving wavy ground. The wavy ground is made of elastic material and installed on a moving belt to simulate the relative motion of the WIG craft and the wavy water surface. The test focuses on the relationship between aerodynamics and the waves and indicates that longitudinal aerodynamics is affected not only by wave height but also by wave height change rate, while the lateral and directional aerodynamic characteristics are less affected by the ground effect. The longitudinal aerodynamics and flight dynamics model considering the wave height change rate are established based on the test results. The waves adopted in the dynamics model are random waves to simulate the natural wave environment better. An H∞ controller is designed to deal with the more complicated wave disturbance. The simulation results show that the aerodynamics and flight dynamics model can reasonably simulate the flight of the WIG craft in the wave environment, and the H∞ controller can effectively deal with the wave disturbance and generate a smooth flight.

Experimental and Numerical Analyses of a Novel Wing-In-Ground Vehicle

The AeroCity is a new form of transportation concept that has been developed to provide high-speed ground transportation at a much lower cost than the existing high-speed railway. Utilizing the Wing-in-Ground (WIG) effect, the AeroCity vehicle does not require complex infrastructures like other contemporary concepts, such as the Hyperloop or Maglev trains. In the current work, the aerodynamic characteristics of the AeroCity vehicle are examined through a Computational Fluid Dynamics (CFD) analysis. The results from the CFD analysis qualitatively match with the findings of wind tunnel experiments. Surface streamlines and boundary layer measurements correspond well with the numerical data. However, the force measurements show a discrepancy. It is found that the separation bubble over the side plates is not captured by the CFD, and this is responsible for an under-prediction of the drag at higher free-stream velocities. The Transition SST model improved the matching between the experiments and numerical simulations. The influence of the moving ground is numerically investigated, and the effect of non-moving ground on the vehicle aerodynamics was found not to be significant. Finally, the inclusion of the track wall is examined. It is found that the merging of the wingtip vortices is responsible for a significant drag increase and, therefore, an alternative track geometry should be investigated.

Hydrodynamic analysis of three oscillating hydrofoils with wing-in-ground effect on power extraction performance

Currently, oscillating-foil power extraction turbines have been developed as a new competitive way compared with rotor blade designs. In the present study, oscillating hydrofoils with a heaving amplitude of one chord at the Reynolds number of Re = 500,000 are employed in a fully prescribed motion to investigate the wing-in-ground (WIG) effect on the power extraction performance. To prescribe the heaving and pitching motions, the harmonic sinusoidal function is actively imposed. An unsteady Reynolds Averaged Navier-Stokes solver based on an open-source CFD code OpenFOAM is used to solve this problem. The fields of the pressure and velocity around a foil are analyzed when the foil approaching and departing from the ground. According to the distribution of pressure on the upper and lower surfaces of the foil, it is found that the efficiency of the power extraction increases mainly due to the increment of the positive pressure on the lower surface. The maximal improvement of the power-extraction efficiency is 7.36% when the minimum gap is 0.25 chord length. A parametric study with different gaps is conducted to predict the optimal power-extraction region. The optimal power-extraction zone shifts to the higher frequency as the gap decreases. The maximal efficiency of the power extraction reaches 41.67%. The wing-in-ground effect turbine (WIGT) by multi-hydrofoils is also simulated and it has a satisfying consequence with the increment of the power-extraction efficiency of 13.37% of the middle hydrofoil which experiences twice the WIG effect.

Effect of Ground Proximity on Aerodynamic Characteristics of NACA 4412 Airfoil.

Ground effect plays a vital role in modulating the flow behavior over any streamlined body. The most widely used wing-in ground effect (WIG) aircrafts and seaplanes utilize this phenomenon in order to enhance the aerodynamic performance during the landing and take-off phases of flight. This paper investigates the aerodynamics of ground effect on a NACA 4412 rectangular wing without end plates. The experiment was conducted in a low-speed wind tunnel at Re=2×105 for the ground clearance of 1 and 0.5 of the chord, measured from the maximum thickness position on the airfoil. The pressure distribution over the chord length was recorded for α=3° and 6° to verify the effect of ground clearance during takeoffs. The results have shown to be in good accordance with the literature, as the coefficient of lift augmented with increase in ground proximity and the induced drag was minimized.

PREDICTION OF HYDRODYNAMIC PERFORMANCE OF 3-D WIG BY IBEM

The hydrodynamic performance of three-dimensional WIG (Wing-In-Ground) vehicle moving with a constant speed above free water surface has been predicted by an Iterative Boundary Element Method (IBEM). IBEM originally developed for 3-D hydrofoils moving under free surface has been modified and extended to 3-D WIGs moving above free water surface. The integral equation based on Green's theorem can be divided into two parts: (1) the wing part, (2) free surface part. These two problems are solved separately, with the effects of one on the other being accounted for in an iterative manner. Both the wing part including the wake surface and the free surface part have been modelled with constant strength dipole and source panels. The effects of Froude number, the height of the hydrofoil from free surface, the sweep, dihedral and anhedral angles on the lift and drag coefficients are discussed for swept and V-type WIGs.

Three-dimensional propulsion characteristics of counter-phase oscillating dual-foil propulsor

A three-dimensional computational study was conducted on the propulsive performance of auto-pitch wing-in-ground effect oscillating foil propulsors (APWIGs) using an unsteady Reynolds Averaged Navier-Stokes solver. This novel propulsor is characterized as the combination of dual-foil configuration and spring-based pitching motion. Both the counter-phase oscillating dual-foil arrangement with produced wing-in-ground (WIG) effect and the auto-pitch mechanism based on attached torsional springs are expected to be favorable for performance improvement. To clearly identify the role of two concerned parameters for APWIGs, the study was divided into two parts of simulations to examine aspect ratio and torsional spring stiffness separately. Firstly, the effect of aspect ratio on the hydrodynamic characteristics was investigated by a fully prescribed oscillating dual-foil configuration. The current computations covering a wide range of aspect ratio from 1 to 10 indicated that the three-dimensional effect tends to dominate the propulsion hydrodynamics with a value of lower than 2. The maximum drop of 14.85% in propulsive efficiency due to the finite-span effect was found at the aspect ratio of 1, while a moderate aspect ratio of 4 leads to an acceptable efficiency loss of 3.22%. Secondly, the three-dimensional hydro-elasticity characteristics of APWIGs as a function of spring stiffness were studied by employing a fixed aspect ratio. A relatively low aspect ratio in which the finite-span effect is still dominant was selected to compare the three-dimensional simulations with two-dimensional predictions. It was observed that the torsional spring stiffness has a significant influence on both hydrodynamic performance and vortex structures of finite-span APWIGs. There exists an optimum spring stiffness for finite-span APWIGs corresponding to the highest efficiency, which resembles the hydro-elasticity characteristics of two-dimensional cases. An averaged efficiency loss of around 10% was reported owing to the low-aspect-ratio effect for three-dimensional APWIGs.

Parameter study on lateral moments of banked wings in ground effect

Ground effect dramatically improves the performance of the Wing-in-Ground (WIG) vehicles near the ground. However, making coordinate turnings in ground effect zone may raise complexity in flight control. The Angle of Attack (AOA) and height are believed to be important factors. To find the impact of these factors, three straight rectangular wings with different aspect ratios are simulated via CFD approach. The results show that in normal situations, the rolling moment tends to level the wing but less effective with the decreasing AOA and changes its direction when the AOA is less than a height dependent value. The yaw moment exhibits complex behavior because two different effects generate oppose moments. The rolling moment coefficient is more influenced by the ground if a wing has larger Aspect Ratio (AR) and works at low to medium AOA. The yawing coefficient is always more influenced if the wing has larger AR regardless AOAs. These findings can provide basic guidance for the design of control system and enable aircraft designers to reshape the crafts to avoid or utilize this effect.

Equations of Flying-Airboat Control Response Determination Movement Due to the Ground Effect

A flying-airboat is a concept of a wing-in-ground (WIG) craft that seeks to take advantage of desirable characteristics within the ground effect, to provide versatile solutions to sea transportation needs in the Southeast Asia region. Previous research has shown that bodies traveling within the ground effect experience an improved lift-to-drag ratio, which translates to significantly better performance. The FAB is a concept that seeks to take advantage of these benefits through a design that facilitates motion entirely within the ground effect. By applying the relevant equations of motion and incorporating various physical design parameters of the concept, a non-linear model can be implemented on the MATLAB/Simulink platform. A simulation of the model shows relative improvements in the performance, response, and stability of the FAB concept subjected to the ground effect as compared to its motion within a free airstream.

A Study on the Relationship between the Design of Aerotrain and Its Stability Based on a Three-Dimensional Dynamic Model

A new generation electric high-speed train called Aerotrain has levitation wings and levitates under Wing-in-Ground (WIG) effect along a U-shaped guideway. The previous study found that lacking knowledge of the design makes the prototype unable to regain stability when losing control. In this paper, the nonlinear three-dimensional dynamic model of the Aerotrain based on the rigid body model has been developed to investigate the relationship between the vehicle body design and its stability. Based on the dynamic model, this paper considered an Aerotrain with a horizontal tail and a vertical tail. To evaluate the stability, the location and area of these tails were parameterized. The effects of these parameters on the longitudinal and directional stability have been investigated to show that: the horizontal tail gives its best performance if the tail area is a function of the tail location; the larger vertical tail area and (or) the farther vertical tail location will give better directional stability. As for the lateral stability, a dihedral front levitation wing design was investigated. This design did not show its effectiveness, therefore a control system is needed. The obtained results are useful for the optimization studies on Aerotrain design as well as developing experimental prototypes.

Influence of ground effect on longitudinal aerodynamic damping of wing-in-ground effect vehicles

ABSTRACTAccurate determination of longitudinal stability characteristics of wing-in-ground (WIG) effect vehicles is an essential step in their design. In order to estimate WIG vehicle’s stability, one needs to determine aerodynamic derivatives, including unsteady ones. The latter are very hard to obtain via wind tunnel tests, so traditionally they are expressed via steady derivatives. The method presented in this paper allows calculating unsteady aerodynamic derivatives by means of Reynolds-averaged Navier–Stokes simulations. The effect of different aerodynamic derivatives on stability characteristics is investigated. It is demonstrated that the decrement is two times greater in case of taking into account the unsteady aerodynamic derivatives calculated according to the presented method.

Stabilizing Attitude Control For Mobility Of Wing In Ground (WIG) Craft - A Review

Wing in ground crafts development have been rapidly advancing in recent years. The current paper reviews the researches and developments of existing stability control system technology’s development and enhancement for wing in ground effect crafts. The review is critically intended for the development of the control system for two-seater Dragonfly 2, a hoverwing type craft. The current review will commence with the introduction on the theory behind the in ground effect phenomenon on the crafts, its regulations and the types of wing in ground crafts, their advantages and disadvantages, and their stability and control issues. This paper also discusses the available attitude control sys-tem types of wing-in-ground craft (WIG), its experiments, simulations and computational methods done especially on both the lon-gitudinal and lateral motion stability.