Effect of chordwise flexibility on propulsive performance of high inertia oscillating-foils

AbstractREGULUS is an Iodine-based electric propulsion system. It has been designed and manufactured at the Italian company Technology for Propulsion and Innovation SpA (T4i). REGULUS integrates the Magnetically Enhanced Plasma Thruster (MEPT) and its subsystems, namely electronics, fluidic, and thermo-structural in a volume of 1.5 U. The mass envelope is 2.5 kg, including propellant. REGULUS targets CubeSat platforms larger than 6 U and CubeSat carriers. A thrust T = 0.60 mN and a specific impulse Isp = 600 s are achieved with an input power of P = 50 W; the nominal total impulse is Itot = 3000 Ns. REGULUS has been integrated on-board of the UniSat-7 satellite and its In-orbit Demonstration (IoD) is currently ongoing. The principal topics addressed in this work are: (i) design of REGULUS, (ii) comparison of the propulsive performance obtained operating the MEPT with different propellants, namely Xenon and Iodine, (iii) qualification and acceptance tests, (iv) plume analysis, (v) the IoD.

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Effects of gradual flexibility and trailing edge shape on propulsive performance of pitching fins

Physics of Fluids ◽

10.1063/5.0055686 ◽

2021 ◽

Vol 33 (7) ◽

pp. 071910

Author(s):

L. Yao ◽

C. Hefler ◽

W. Shyy ◽

H. H. Qiu

Keyword(s):

Trailing Edge ◽

Propulsive Performance

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Comparative investigations in the effect of angle of attack profile on hydrodynamic performance of bio-inspired foil, (corrected)

Journal of Naval Architecture and Marine Engineering ◽

10.3329/jname.v10i2.14229 ◽

2013 ◽

Vol 10 (2) ◽

pp. 99-108 ◽

Cited By ~ 2

Author(s):

J. A. Esfahani ◽

E. Barati ◽

Hamid Reza Karbasian

Keyword(s):

Angle Of Attack ◽

Underwater Vehicles ◽

Hydrodynamic Performance ◽

Profile Function ◽

Flapping Foil ◽

Propulsive Performance ◽

Wide Range ◽

Effective Angle ◽

Thrust Production ◽

Optimum Profile

In flapping underwater vehicles the propulsive performance of harmonically sinusoidal heaving and pitching foil will be degraded by some awkward changes in effective angle of attack profile, as the Strouhal number increases. This paper surveys different angle of attack profiles (Sinusoidal, Square, Sawtooth and Cosine) and considers their thrust production ability. In the wide range of Strouhal numbers, thrust production of Square profile is considerable but it has a discontinuity in heave velocity profile, in which an infinite acceleration exists. This problem poses a significant defect in control of flapping foil. A novel profile function is proposed to omit sharp changes in heave velocity and acceleration. Furthermore, an optimum profile is found for different Strouhal numbers with respect to Square angle of attack profile.DOI: http://dx.doi.org/10.3329/jname.v10i2.14229

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Oscillating foils of high propulsive efficiency

Journal of Fluid Mechanics ◽

10.1017/s0022112097008392 ◽

1998 ◽

Vol 360 ◽

pp. 41-72 ◽

Cited By ~ 757

Author(s):

J. M. ANDERSON ◽

K. STREITLIEN ◽

D. S. BARRETT ◽

M. S. TRIANTAFYLLOU

Keyword(s):

Reynolds Number ◽

High Efficiency ◽

Leading Edge ◽

Half Cycle ◽

Trailing Edge ◽

Propulsive Efficiency ◽

Principal Characteristics ◽

Theoretical Predictions ◽

Power Measurements ◽

Oscillating Foils

Thrust-producing harmonically oscillating foils are studied through force and power measurements, as well as visualization data, to classify the principal characteristics of the flow around and in the wake of the foil. Visualization data are obtained using digital particle image velocimetry at Reynolds number 1100, and force and power data are measured at Reynolds number 40 000. The experimental results are compared with theoretical predictions of linear and nonlinear inviscid theory and it is found that agreement between theory and experiment is good over a certain parametric range, when the wake consists of an array of alternating vortices and either very weak or no leading-edge vortices form. High propulsive efficiency, as high as 87%, is measured experimentally under conditions of optimal wake formation. Visualization results elucidate the basic mechanisms involved and show that conditions of high efficiency are associated with the formation on alternating sides of the foil of a moderately strong leading-edge vortex per half-cycle, which is convected downstream and interacts with trailing-edge vorticity, resulting eventually in the formation of a reverse Kármán street. The phase angle between transverse oscillation and angular motion is the critical parameter affecting the interaction of leading-edge and trailing-edge vorticity, as well as the efficiency of propulsion.

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Evaluation of propulsive performance of a tanker in damaged conditions

Hydrodynamics VI: Theory and Applications ◽

10.1201/b16815-24 ◽

2004 ◽

pp. 159-165

Author(s):

J Yang ◽

S Rhee ◽

J Lee ◽

H Kim

Keyword(s):

Propulsive Performance

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Fin sweep angle does not determine flapping propulsive performance

10.1101/2020.11.03.366997 ◽

2020 ◽

Author(s):

Andhini N. Zurman-Nasution ◽

Bharathram Ganapathisubramani ◽

Gabriel D. Weymouth

Keyword(s):

Correlation Coefficient ◽

Large Range ◽

Three Dimensional ◽

Leading Edge ◽

Potential Sweep ◽

Sweep Angle ◽

Propulsive Performance ◽

Maximum Angle ◽

And Robotics ◽

Three Dimensional Simulations

The importance of the leading-edge sweep angle of propulsive surfaces used by unsteady swimming and flying animals has been an issue of debate for many years, spurring studies in biology, engineering, and robotics with mixed conclusions. In this work we provide results from an extensive set of three-dimensional simulations of finite foils undergoing tail-like (pitch-heave) and flipper-like (twist-roll) kinematics for a range of sweep angles while carefully controlling all other parameters. No significant change in force and power is observed for tail-like motions as the sweep angle increases, with a corresponding efficiency drop of only ≈ 2%. Similar findings are seen in flipper-like motion and the overall correlation coefficient between sweep angle and propulsive performance is 0.1-6.7%. This leads to a conclusion that fish tails or mammal flukes can have a large range of potential sweep angles without significant negative propulsive impact. A similar conclusion applies to flippers; although there is a slight benefit to avoid large sweep angles for flippers, this could be easily compensated by adjusting other hydrodynamics parameters such as flapping frequency, amplitude and maximum angle of attack to gain higher thrust and efficiency.

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Plume flowfield and propulsive performance analysis of a rotating detonation engine

Aerospace Science and Technology ◽

10.1016/j.ast.2018.08.024 ◽

2018 ◽

Vol 81 ◽

pp. 383-393 ◽

Cited By ~ 15

Author(s):

Jian Sun ◽

Jin Zhou ◽

Shijie Liu ◽

Zhiyong Lin ◽

Wei Lin

Keyword(s):

Performance Analysis ◽

Propulsive Performance ◽

Rotating Detonation Engine ◽

Detonation Engine ◽

Rotating Detonation

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Contrarotating Propeller Propulsion— A State-of-the-Art Report

Marine Technology and SNAME News ◽

10.5957/mt1.1969.6.3.281 ◽

1969 ◽

Vol 6 (03) ◽

pp. 281-290

Author(s):

J. B. Hadler

Keyword(s):

State Of The Art ◽

Model Tests ◽

Performance Data ◽

Ship Propulsion ◽

Propulsive Performance ◽

Merchant Ship ◽

Current Alternative ◽

Twin Screw ◽

Vibration Problems

This report presents a synthesis of existing knowledge, albeit limited, on CRP as applicable to merchant ship propulsion. It presents propulsive performance data for two types of ships, tankers and containerships, based on model tests, and discusses briefly the stopping, cavitation, and propeller-induced vibration problems of CRP. From the analysis it appears that the greatest potential for employment of such a propulsive device, offering significant reductions in installed shp, is on high-powered, fine-formed ships for which the only current alternative is a twin-screw installation.

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