Calculation of the Aerodynamic Forces on Automotive Lifting Surfaces

1985 ◽  
Vol 107 (4) ◽  
pp. 438-443 ◽  
Author(s):  
J. Katz
Keyword(s):  
Steady State ◽  
Vortex Lattice ◽  
Numerical Technique ◽  
Angle Of Attack ◽  
Ground Effect ◽  
Aerodynamic Forces ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Close Proximity ◽  
Lifting Surfaces

A numerical technique was developed to investigate the performance of automotive lifting surfaces in close proximity to ground. The model is based on the Vortex Lattice Method and includes freely-deforming wake elements. The ground effect was simulated by reflection and both steady and unsteady pressures and loads on various wing planforms were considered. Calculated results are presented for wings having both positive and negative incidences, with and without ground effect. Also the transient lift of a wing in a plunging motion was analyzed in ground proximity and at a negative angle of attack. Finally the periodic lift fluctuations on the front winglet of a racing car, due to its suspension oscillations, were calculated and found to exceed approximately twice the steady-state value.

A Study on Estimation of Propulsive Power for Wing in Ground Effect (WIG) Craft to Take-off

2012 ◽  
pp. 43-51 ◽  
Author(s):  
A. Priyanto ◽  
A. Maimun ◽  
S. Noverdo ◽  
J. Saeed ◽  
A. Faizal ◽  
...  
Keyword(s):  
Vortex Lattice ◽  
Surface Effect ◽  
Aerodynamic Drag ◽  
Ground Effect ◽  
Lattice Method ◽  
Flight Tests ◽  
Vortex Lattice Method ◽  
Design Speed ◽  
Propulsive Power ◽  
Wing In Ground Effect

This paper estimated the propulsive power required for Wing in Ground effect (WIG) craft to take-off. The hull form design of the WIG craft incorporates a stepped planing triple hull, since the planing hull is well known to give result and assist in lifting off the water surface effect. In order to determine the power required for WIG craft to take-off, the craft prototype was built into 1 to 6 model scale. In numerical calculation, the required thrust motor of model to take-off was calculated by summation of water drag; aerodynamic drag and the weight of model. The water drag was estimated by Savitsky’s method, and the aerodynamic drag by a MATLAB programming based on Vortex Lattice Method (VLM). In the experiments, the relationship propeller RPM against thrust motor was obtained from the calibration tests. At the flight tests of the model, the propeller RPM of the model was measured to determine the total thrust motor and the propulsive power required to take-off by using the Froude’s Momentum Theory. The required propulsive power for craft scaled model was found to give the total thrusts of 33.85 N, and the effective power estimates required for WIG model to take-off per propeller was 128Watt at the design speed. It was also observed during most of the flight tests, the craft is attempting to enter into ground surface effect at design speed. Kertas kerja ini mengira jumlah kuasa bagi bot Wing in Ground effect (WIG) untuk terbang. Perekabentuk bot WIG menggunakan badan bot planing, yang terkenal untuk membantu dan mengangkat badan bot ke atas permukaan air. Dalam mendapatkan kuasa bagi bot WIG untuk terbang, model bot dibina dalam skala 1 berbanding 6. Pengiraan kuasa bagi model WIG adalah pengiraan jumlah rintangan model pada setiap halaju, terhadap tambahan rintangan udara, rintangan air dengan jisim model. Kaedah yang digunakan dalam pengiraan jumlah rintangan model adalah dua kaedah iaitu kaedah berangka dan eksperimen. Dari kaedah berangka, rintangan air telah dikira menggunakan simulasi Savitsky, dan rintangan udara telah dikira menggunakan simulasi MATLAB berasaskan kaedah Vortex Lattice Method (VLM). Dari kaedah eksperimen, ujian kalibrasi dilakukan terlebih dahulu untuk mendapatkan hubungan antara RPM melawan daya dorong. Kemudian ujian terbang dilakukan untuk mendapatkan RPM untuk setiap halaju model sebelum terbang. Nilai RPM daripada ujian ini digunakan untuk mendapatkan jumlah daya dorong daripada ujian kalibrasi dan jumlah kuasa didapatkan dengan menggunakan persamaan hukum Froude’s Momentum. Keputusan jumlah daya dorong bagi model diperlukan untuk terbang daripada dua kaedah adalah 33.85 N, dan jumlah kuasa untuk satu kipas iaitu 128Watt. Daripada pengamatan ujian terbang, model WIG telah terbang dalam Ground Effect (GE) di atas permukaan air.

Comparison of Tacking and Wearing Performance Between a Japanese Traditional Square Rig and a Chinese Lug Rig

2005 ◽  
Author(s):  
Yutaka Masuyama ◽  
Akira Sakurai ◽  
Toichi Fukas ◽  
Kazunori Aoki
Keyword(s):  
Wind Tunnel ◽  
Vortex Lattice ◽  
Aerodynamic Performance ◽  
Measured Data ◽  
The Other ◽  
Aerodynamic Forces ◽  
Lattice Method ◽  
Wind Tunnel Tests ◽  
Vortex Lattice Method ◽  
Force Variation

Aerodynamic performance of a Japanese traditional square rig, “Bezai-ho”, and a Chinese lug rig, “Shinshi-bo” in Japanese, were studied by means of wind tunnel tests, sea trials and numerical calculations. Sail forces and sail shapes were measured in the wind tunnel tests. A sail dynamometer boat Fujin was employed for the sea trials, by which aerodynamic forces acting on sail, sail shapes, and sailing conditions of the boat can be measured at the same time. Using the measured sail shapes, sail forces are calculated by means of a vortex lattice method. Differences of sail performance of the above mentioned two types of rig were clarified in the wind tunnel tests and sea trials. The calculated sail performance shows good agreements with the measured data in upwind condition. Dynamic sail performance of the two types of rig during tacking and wearing operations was also clarified in the sea trials using the boat Fujin. Details of sail force variation in time during maneuvering can be investigated by the sail dynamometer system. For the “Bezai-ho,” the backward force acting on sail when the boat changes tacks (wind over the bow) was investigated. At this moment, the square sail falls into a “caught aback” situation, which makes the tacking operation difficult. On the other hand, “Shinshi-bo” showed good steady performance similar to that of the modern marconi rig, and good tacking performance. Obtained results of steady and dynamic sail performance in this paper provide useful information for sail trimming and maneuvering of boats equipped with the western square rigs and modern lug rig introduced by H.G. Hasler.

Modified Unsteady Vortex Lattice Method for Aerodynamics of Flapping Wing Models

2015 ◽  
Author(s):  
Anh Tuan Nguyen ◽  
Jae-Hung Han
Keyword(s):  
Vortex Lattice ◽  
Micro Air Vehicles ◽  
Flapping Wing ◽  
Preliminary Design ◽  
Aerodynamic Forces ◽  
Lattice Method ◽  
Real Motion ◽  
Flapping Motion ◽  
The Real ◽  
Vortex Lattice Method

Motivated by extensive possible applications of flapping-wing micro-air vehicles (MAVs) to various different areas, there has been an increasing amount of research related to this issue. In the stage of preliminary studies, one of the most important tasks is to predict the aerodynamic forces generated by the flapping motion. Studying aerodynamics of insects is an efficient way to approach the preliminary design of flapping-wing MAVs. In this paper, a modified version of an Unsteady Vortex Lattice Method (UVLM) is developed to compute aerodynamic forces appearing in flapping-wing models. A hawkmoth-like wing with kinematics based on the real motion is used for the simulations in this paper.

scholarly journals Predicting Rotor Heat Transfer Using the Viscous Blade Element Momentum Theory and Unsteady Vortex Lattice Method

Aerospace ◽  
2020 ◽  
Vol 7 (7) ◽  
pp. 90
Author(s):  
Abdallah Samad ◽  
Gitsuzo B. S. Tagawa ◽  
François Morency ◽  
Christophe Volat
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Vortex Lattice ◽  
Ground Effect ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Blade Element Momentum Theory ◽  
Momentum Theory ◽  
Blade Element

Calculating the unsteady convective heat transfer on helicopter blades is the first step in the prediction of ice accretion and the design of ice-protection systems. Simulations using Computational Fluid Dynamics (CFD) successfully model the complex aerodynamics of rotors as well as the heat transfer on blade surfaces, but for a conceptual design, faster calculation methods may be favorable. In the recent literature, classical methods such as the blade element momentum theory (BEMT) and the unsteady vortex lattice method (UVLM) were used to produce higher fidelity aerodynamic results by coupling them to viscous CFD databases. The novelty of this research originates from the introduction of an added layer of the coupling technique to predict rotor blade heat transfer using the BEMT and UVLM. The new approach implements the viscous coupling of the two methods from one hand and introduces a link to a new airfoil CFD-determined heat transfer correlation. This way, the convective heat transfer on ice-clean rotor blades is estimated while benefiting from the viscous extension of the BEMT and UVLM. The CFD heat transfer prediction is verified using existing correlations for a flat plate test case. Thrust predictions by the implemented UVLM and BEMT agree within 2% and 80% compared to experimental data. Tip vortex locations by the UVLM are predicted within 90% but fail in extreme ground effect. The end results present as an estimate of the heat transfer for a typical lightweight helicopter tail rotor for four test cases in hover, ground effect, axial, and forward flight.

Generalized vortex lattice method for planar supersonic flow

AIAA Journal ◽  
1997 ◽  
Vol 35 ◽  
pp. 1230-1233
Author(s):  
Paulo A. O. Soviero ◽  
Hugo B. Resende
Keyword(s):  
Supersonic Flow ◽  
Vortex Lattice ◽  
Lattice Method ◽  
Vortex Lattice Method

scholarly journals Static Aeroelastic Characteristics of Morphing Trailing-Edge Wing Using Geometrically Exact Vortex Lattice Method

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Sen Mao ◽  
Changchuan Xie ◽  
Lan Yang ◽  
Chao Yang
Keyword(s):  
Vortex Lattice ◽  
Deflection Angle ◽  
Aircraft Design ◽  
Analysis Method ◽  
Lattice Method ◽  
Trailing Edge ◽  
Vortex Lattice Method ◽  
Analysis And Design ◽  
Aeroelastic Analysis ◽  
Typical Model

A morphing trailing-edge (TE) wing is an important morphing mode in aircraft design. In order to explore the static aeroelastic characteristics of a morphing TE wing, an efficient and feasible method for static aeroelastic analysis has been developed in this paper. A geometrically exact vortex lattice method (VLM) is applied to calculate the aerodynamic forces. Firstly, a typical model of a morphing TE wing is chosen and built which has an active morphing trailing edge driven by a piezoelectric patch. Then, the paper carries out the static aeroelastic analysis of the morphing TE wing and corresponding simulations were carried out. Finally, the analysis results are compared with those of a traditional wing with a rigid trailing edge using the traditional linearized VLM. The results indicate that the geometrically exact VLM can better describe the aerodynamic nonlinearity of a morphing TE wing in consideration of geometrical deformation in aeroelastic analysis. Moreover, out of consideration of the angle of attack, the deflection angle of the trailing edge, among others, the wing system does not show divergence but bifurcation. Consequently, the aeroelastic analysis method proposed in this paper is more applicable to the analysis and design of a morphing TE wing.

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