Investigation of the Possibilities of Rotating Cylinders as an Auxiliary Lift Device

1964 ◽  
Vol 68 (647) ◽  
pp. 777-780
Author(s):  
J. E. Chacksfield
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Experimental Studies ◽  
Rotating Cylinder ◽  
Test Results ◽  
Major Research ◽  
Drag Coefficients ◽  
Magnus Effect ◽  
The One ◽  
Gains And Losses

The following is an attempt to show the gains and losses achieved when a rotating cylinder is used to create additional lift during the take-off and landing of an aircraft.A hundred-year old theory lies behind the results (the “Magnus” effect), which, up to the present day has not been put to practical use in flight for increasing CL. Many proposals and tentative designs have been studied at major Research Establishments, notably A.V.A. Gottingen and the RAE but experimental studies on aircraft converted for the purpose have yet to be made.Limited test results show that the CL on a rotating cylinder can be as great as 15 providing that sufficient care is taken to approach infinite aspect ratio by means of end-plates on a high aspect ratio cylinder. The one great disadvantage with the cylinder is the high drag coefficients produced. However, there seems no reason why a fairing should not be placed in the wake to reduce the drag to that corresponding to a blunt-nosed thick aerofoil section.

scholarly journals Efficient non-halogenated solvent for the template-free solution synthesis of ultralong copper octaethylporphyrin nanowire networks with strong photoswitching properties

RSC Advances ◽  
2017 ◽  
Vol 7 (14) ◽  
pp. 8151-8155 ◽  
Author(s):  
Jia-Jia Li ◽  
Hong-Dan Peng ◽  
Li-Yi Shi ◽  
Hao-Di Wu ◽  
Ge-Bo Pan
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Free Solution ◽  
Solution Synthesis ◽  
Semiconducting Nanowires ◽  
One Step ◽  
Template Free ◽  
Scalable Synthesis ◽  
The One ◽  
Nanowire Networks

A non-halogenated solvent was used for the one-step and scalable synthesis of extremely high aspect ratio organic semiconducting nanowires of CuOEP which exhibit excellent photoswitching effects with reliable reproducibility and superior stability.

Effect of Speed Ratio and Axial Spacing Variations on the Performance of a High Aspect Ratio, Low Speed Contra-Rotating Fan

2012 ◽  
Author(s):  
Chetan S. Mistry ◽  
A. M. Pradeep
Keyword(s):  
Aspect Ratio ◽  
Numerical Simulations ◽  
High Aspect Ratio ◽  
Total Pressure ◽  
Experimental Studies ◽  
Pressure Rise ◽  
Operating Conditions ◽  
Speed Ratio ◽  
Stall Margin ◽  
Low Speed

This paper explores the effect of speed ratio and axial spacing between high aspect ratio, low speed contra-rotating pair rotors on their aerodynamic performance. The blades were designed with a low hub-tip ratio of 0.35 and an aspect ratio of 3.0. Numerical and experimental studies are carried out on these contra-rotating rotors operating at a Reynolds number of 1.258 × 105 (based on blade chord). The first and second rotors were designed to develop a pressure rise of 1100 Pa and 900 Pa, respectively, for total mass flow rate of 6 kg/s when both operating at a design speed of 2400 rpm. The performance of the fan was evaluated based on variations of total pressure and flow angles at off-design operating conditions. The measurementsof total pressure rise, flow angles etc. are taken upstream of the first rotor and in between the two rotors and downstream of the second rotor. The performance of the contra rotating stage is mainly influenced by the axial spacing between the rotors and speed ratio of both the rotors. The study reveals that the aerodynamics of the contra-rotating stage and stall margin is significantly affected by both the speed ratio as well as the axial spacing between the rotors. It was found that with increasing the speed ratio, the strong suction generated by the second rotor, improves the stage pressure rise and stall margin. Lower axial spacing changes the flow incidence to the second rotor and thereby improves the overall performance of the stage. This however, is accompanied by an increased noise level. The performance is investigated at different speed ratios of the rotors at varying axial spacing. Detailed numerical simulations have been conducted using ANSYS CFX13© using mixing plane approach between rotors. Numerical simulations are compared with experimental results at off-design conditions. These results are validated using the experimental data. Numerical simulations are expected to provide deeper insight into the flow physics of contra-rotating rotors which may be difficult to capture experimentally.

Fabrication and Testing of Micro Corona Motor and Micro Gas Bearings

2004 ◽  
Author(s):  
Daejong Kim ◽  
Sanghoon Lee ◽  
Michael D. Bryant
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Geometric Constraints ◽  
Test Results ◽  
X Ray ◽  
Gas Bearings ◽  
Performance Requirements ◽  
Tall Structures ◽  
Gas Bearing ◽  
Bearing System

The paper introduces fabrication processes of a micro corona motor and micro gas bearings via X-ray lithography. The micro corona motor was fabricated using a membrane-less built-on X-ray mask. The motor principle requires axially thick sharp stator electrodes. Therefore, X-ray lithography was adopted for precise, high aspect ratio characteristics. To minimize diffraction, a built-on X-ray mask (conformal mask) technique was employed with negative toned SU-8 photo resist. This technique may be suitable for fast fabrication of prototypes or very tall structures, which can be largely affected by printing gaps. Micro gas bearings were fabricated as a viable bearing system for the micro corona motor. Timembrane mask was fabricated to meet the strict performance requirements and geometric constraints of the micro gas bearing. Test results of the micro gas bearings and micro corona motor are also presented.

scholarly journals Computational Analysis of the Rotating Cylinder Embedment onto Flat Plate

CFD Letters ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 133-149
Author(s):  
Hidayatullah Mohammad Ali ◽  
Azmin Shakrine Mohd Rafie ◽  
Syaril Azrad Md Ali ◽  
Ezanee Gires
Keyword(s):  
Flat Plate ◽  
Flow Analysis ◽  
Rotating Cylinder ◽  
Past Century ◽  
Foundation Design ◽  
The Past ◽  
Aerodynamic Properties ◽  
Magnus Effect ◽  
Two Dimensional Flow ◽  
The One

The Magnus effect and its evolution have greatly affected the aerospace industry over the past century to date. Nevertheless, cylinder embedment onto a flat plate offers a new discovery that is yet to be investigated, specifically whether the concept could enhance the aerodynamic properties of the flat plate following the Magnus effect momentum injection. Over the past decade, the use of a rotating cylinder on an aerofoil has existed from past researches studies where the embedment has significantly increased in its aerodynamic performance better than the one without Magnus application. However, it would be hard to achieve experimental-wise as an accurate measurement and fabrication would be needed to have the same resulting effects. Here, most of the researchers would not focus deeply on the placement of the cylinder as this may increase their fabrication and testing complications. Therefore, the current study delineates the use of flat plate as the foundation design to encounter the arise matter by reducing its complication yet easy to manufacture experimentally. In this work, the model output was evaluated by using ANSYS WORKBENCH 2019 software to simulate two-dimensional flow analysis for the rotational velocities of 500 RPM and 1000 RPM, respectively. This was done for different Reynolds numbers ranging from 4.56E+05 to 2.74E+06 which implicitly implied with free stream velocities varying from 5 m/s to 30 m/s for different angles of attack between 0 to 20 degrees. Prior to developing the best model embedment, the mesh independency test was validated with an error of less than 1%. The study resulted in a remarkable trend that was noticeably up to 32% (500 RPM) and 76% (1000 RPM) better in compared to the one without momentum injection. Similarly, the high recovery led to a tremendously lower of 51% (500 RPM) and 99% (1000 RPM), respectively. In sum, these findings generated a stall angle delay of up to 26% (500 RPM) and 78% (1000 RPM) accordingly.

Asymptotic theory of high-aspect-ratio arched wings in steady incompressible flow

1995 ◽  
Vol 303 ◽  
pp. 367-377 ◽  
Author(s):  
G. Iosilevskii
Keyword(s):  
Aspect Ratio ◽  
Incompressible Flow ◽  
High Aspect Ratio ◽  
Load Distribution ◽  
Asymptotic Theory ◽  
Order Approximation ◽  
The Other ◽  
Integral Formulation ◽  
Circular Arc ◽  
The One

Asymptotic theory of high-aspect-ratio wings in steady incompressible flow is extended to a case where the wing forms either an open or closed circular arc. The generalization is based on an integral formulation of the problem, which resembles the one used by Guermond (1990) for a plane curved wing. A second-order approximation is obtained for the load distribution on two model wings, one resembling that of a gliding parachute, and the other resembling a short duct.

scholarly journals Flettner Rotor Concept for Marine Applications: A Systematic Study

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
A. De Marco ◽  
S. Mancini ◽  
C. Pensa ◽  
G. Calise ◽  
F. De Luca
Keyword(s):  
Aspect Ratio ◽  
Systematic Study ◽  
Rotating Cylinder ◽  
Navier Stokes ◽  
Preliminary Design ◽  
Mathematical Tool ◽  
Drag Coefficients ◽  
Simulation Results ◽  
Marine Applications ◽  
Lift And Drag

The concept of Flettner rotor, a rotating cylinder immersed in a fluid current, with a top-mounted disk, has been analyzed by means of unsteady Reynolds averaged Navier-Stokes simulations, with the aim of creating a suitable tool for the preliminary design of the Flettner rotor as a ship’s auxiliary propulsion system. The simulation has been executed to evaluate the performance sensitivity of the Flettner rotor with respect to systematic variations of several parameters, that is, the spin ratio, the rotor aspect ratio, the effect of the end plates, and their dimensions. The Flettner rotor device has been characterized in terms of lift and drag coefficients, and these data were compared with experimental trends available in literature. A verification study has been conducted in order to evaluate the accuracy of the simulation results and the main sources of numerical uncertainty. All the simulation results were used to achieve a surrogate model of lift and drag coefficients. This model is an effective mathematical tool for the preliminary design of Flettner rotor. Finally, an example of assessment of the Flettner rotor performance as an auxiliary propulsion device on a real tanker ship is reported.

scholarly journals PENGARUH PENGGUNAAN DAUN KEMANGI DAN KULIT JERUK NIPIS PADA PROSES PENCUCIAN ALAT MAKAN TERHADAP ANGKA KUMAN

2018 ◽  
Vol 6 (2) ◽  
pp. 158-163
Author(s):  
Dewi Safitri ◽  
Yusmidiarti Yusmidiarti ◽  
Elly Wahyuni
Keyword(s):  
Experimental Studies ◽  
Volatile Oil ◽  
Ocimum Sanctum ◽  
Control Group ◽  
Test Results ◽  
Control Group Design ◽  
Group Design ◽  
Washing Process ◽  
The One ◽  
One Way Anova

The process of washing utensils in the coto stall Minggu market  still not meet the standard number of germs cutlery of allowed. Water used in the washing process is physically still do not meet the requirements because of water used repeatedly without being replaced in a day. These conditions could affect the health of consumers caused by washing utensils the lack of clean and unhygienic. Basil leaves and leather lime with the flavonoid and volatile oil can reduce the number of germs cutlery. Known effect of the use of basil leaves and leather lime in the process of washing utensils on the number of germs. Experimental studies with Posttest Only Control Group Design. Location of research conducted at the soup stall Minggu Market, of Ratu Samban District, City of Bengkulu. The subjects of this research is a leaf of basil (Ocimum sanctum) and the leather lime (Citrus aurantifolia). Research object is the number of germs cutlery. Test used is the One Way Anova. Research using 6 basil leaves and 1 small leather lime can reduce the number of germs cutlery. The One Way Anova test results are known significant value 0,028 < 0,05. This means that there are significant differences between the number of bacterial colonies the control group, basil and leather lime on the number of germs cutlery.

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