Experimental Research on a Novel Design of Variable Area Caudal Fin

2013 ◽  
Vol 461 ◽  
pp. 206-212
Author(s):  
Bo Liu ◽  
Lei Wang ◽  
Bu Yao Chen ◽  
Feng Hua Qin ◽  
Shi Wu Zhang
Keyword(s):  
High Efficiency ◽  
Thrust Force ◽  
Lateral Force ◽  
The Novel ◽  
Kinematic Parameters ◽  
Fish Swimming ◽  
Caudal Fin ◽  
Propulsion Performance ◽  
Novel Design ◽  
Propulsive Mechanism

Caudal fin has fascinated researchers for decades for their great role in fish swimming, and researchers have developed lots of designs of caudal fin to achieve high efficiency and speed propulsion. This paper presents a novel design of variable area caudal fin. A “window” which can rotate freely is designed in the middle of the fin and it can be opened by the fluid force and closed by a simple mechanism. By closing or opening the “window”, the caudal fin can vary its area dynamically in the out-stroke and in-stroke in its motion. Four modes to control the “window” in the pitching motion is then presented, their hydrodynamic forces including thrust force, lateral force and lift force are studied. It is found out that the variable area fin model can indeed improve the propulsion performance compared with the traditional fin, and the mode of closing the “window” in the out-stroke and opening the “window” in the in-stroke can generate the largest thrust force for our model than the other modes. Moreover, experiments about various kinematic parameters with different modes are conducted, it is found out different modes behave quite different with same pitching frequency and amplitude, and its propulsive performance is highly depend on the kinematic parameters. The variable area caudal fin model casts an inspiration for the novel design of underwater propulsive mechanism and the results will be useful for the propulsion study of underwater bio-mimetic vehicles.

Tail shapes lead to different propulsive mechanisms in the body/caudal fin undulation of fish

2020 ◽  
pp. 095440622096768
Author(s):  
Jialei Song ◽  
Yong Zhong ◽  
Ruxu Du ◽  
Ling Yin ◽  
Yang Ding
Keyword(s):  
Numerical Simulation ◽  
Aspect Ratio ◽  
High Efficiency ◽  
The Body ◽  
Caudal Fin ◽  
Fish Model ◽  
Swimming Efficiency ◽  
Simulation Results ◽  
Propulsive Mechanism ◽  
High Depth

In this paper, we investigate the hydrodynamics of swimmers with three caudal fins: a round one corresponding to snakehead fish ( Channidae), an indented one corresponding to saithe ( Pollachius virens), and a lunate one corresponding to tuna ( Thunnus thynnus). A direct numerical simulation (DNS) approach with a self-propelled fish model was adopted. The simulation results show that the caudal fin transitions from a pushing/suction combined propulsive mechanism to a suction-dominated propulsive mechanism with increasing aspect ratio ( AR). Interestingly, different from a previous finding that suction-based propulsion leads to high efficiency in animal swimming, this study shows that the utilization of suction-based propulsion by a high- AR caudal fin reduces swimming efficiency. Therefore, the suction-based propulsive mechanism does not necessarily lead to high efficiency, while other factors might play a role. Further analysis shows that the large lateral momentum transferred to the flow due to the high depth of the high- AR caudal fin leads to the lowest efficiency despite the most significant suction.

scholarly journals The Analysis of Biomimetic Caudal Fin Propulsion Mechanism with CFD

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Guijie Liu ◽  
Shuikuan Liu ◽  
Yingchun Xie ◽  
Dingxin Leng ◽  
Guanghao Li
Keyword(s):  
High Efficiency ◽  
High Mobility ◽  
Caudal Fin ◽  
Propulsion Performance ◽  
Propulsion Force ◽  
St Number ◽  
Underwater Movement ◽  
The Mathematical Model ◽  
Bionic Propulsion ◽  
Bionic Underwater Robot

In nature, fish not only have extraordinary ability of underwater movement but also have high mobility and flexibility. The low energy consumption and high efficiency of fish propulsive method provide a new idea for the research of bionic underwater robot and bionic propulsive technology. In this paper, the swordfish was taken as the research object, and the mechanism of the caudal fin propulsion was preliminarily explored by analyzing the flow field structure generated by the swing of caudal fin. Subsequently, the influence of the phase difference of the heaving and pitching movement, the swing amplitude of caudal fin, and Strouhal number (St number) on the propulsion performance of fish was discussed. The results demonstrated that the fish can obtain a greater propulsion force by optimizing the motion parameters of the caudal fin in a certain range. Lastly, through the mathematical model analysis of the tail of the swordfish, the producing propulsive force principle of the caudal fin and the caudal peduncle was obtained. Hence, the proposed method provided a theoretical basis for the design of a high-efficiency bionic propulsion system.

A Novel Design and Implementation of a Lightweight Energy-Efficient Robotic Fish

2015 ◽  
Vol 719-720 ◽  
pp. 298-305
Author(s):  
Qin Yan ◽  
Wen Shang ◽  
Jun Zhong ◽  
Qi Xin Zhu
Keyword(s):  
Energy Consumption ◽  
Energy Efficient ◽  
Low Energy ◽  
The Novel ◽  
Performance Study ◽  
Kinematic Parameters ◽  
Magnetomotive Force ◽  
Design And Implementation ◽  
Low Energy Consumption ◽  
Novel Design

Inspired by the astonishing ability of the fish, more and more researchers devote themselves to improving the performance of the underwater robotic propeller. In this paper, a novel design and a preliminary performance study of a lightweight robofish are presented. Firstly, the principle of the actuator by magnetomotive force is introduced. Secondly, the implementation of the biomimetic robofish is investigated. Finally, several expriments are conducted to explore the energy consumption of the magnetomoive force actuator and the affection of the kinematic parameters on the velocity. The experimental results reveal that the novel biomimetic robofish driven by magnetomotive force has a low energy consumption and shows good performance in swimming.

A New 1.7MW Industrial Gas Turbine: The Ruston Hurricane

1991 ◽  
Author(s):  
A. T. Sanders ◽  
M. H. Tothill ◽  
G. R. Wood
Keyword(s):  
Gas Turbine ◽  
High Efficiency ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Thermodynamic Efficiency ◽  
The Novel ◽  
Exhaust Temperature ◽  
High Pressure Ratio ◽  
Industrial Gas Turbine ◽  
Novel Design

The paper describes the design of a compact new 1.7MW (2300hp) single shaft industrial gas turbine and package, with high efficiency and exhaust temperature ideal for industrial congeneration applications. These advantages are obtained with a high pressure ratio single stage centrifugal compressor, single high temperature combustor and two-stage axial flow turbine using only one row of cooled blades. The novel design features are described with the associated development testing. A typical installation is also described showing the potential for very high overall thermodynamic efficiency.

scholarly journals Recent Advancements in Polythiophene-Based Materials and Their Biomedical, Geno Sensor and DNA Detection

2021 ◽  
Vol 22 (13) ◽  
pp. 6850
Author(s):  
Seyyed Mojtaba Mousavi ◽  
Seyyed Alireza Hashemi ◽  
Sonia Bahrani ◽  
Khadije Yousefi ◽  
Gity Behbudi ◽  
...  
Keyword(s):  
Biomedical Engineering ◽  
High Efficiency ◽  
Polymeric Materials ◽  
The Novel ◽  
Electrode Coating ◽  
Effective Response ◽  
Hiv Drugs ◽  
New Generation ◽  
New Compounds ◽  
Anti Hiv

In this review, the unique properties of intrinsically conducting polymer (ICP) in biomedical engineering fields are summarized. Polythiophene and its valuable derivatives are known as potent materials that can broadly be applied in biosensors, DNA, and gene delivery applications. Moreover, this material plays a basic role in curing and promoting anti-HIV drugs. Some of the thiophene’s derivatives were chosen for different experiments and investigations to study their behavior and effects while binding with different materials and establishing new compounds. Many methods were considered for electrode coating and the conversion of thiophene to different monomers to improve their functions and to use them for a new generation of novel medical usages. It is believed that polythiophenes and their derivatives can be used in the future as a substitute for many old-fashioned ways of creating chemical biosensors polymeric materials and also drugs with lower side effects yet having a more effective response. It can be noted that syncing biochemistry with biomedical engineering will lead to a new generation of science, especially one that involves high-efficiency polymers. Therefore, since polythiophene can be customized with many derivatives, some of the novel combinations are covered in this review.

Calculation and Measurement of the Stiffness and Damping Coefficients for a Low Impedance Hydrodynamic Bearing

1997 ◽  
Vol 119 (1) ◽  
pp. 57-63 ◽  
Author(s):  
M. J. Goodwin ◽  
P. J. Ogrodnik ◽  
M. P. Roach ◽  
Y. Fang
Keyword(s):  
Experimental Data ◽  
Dynamic Stiffness ◽  
Perturbation Technique ◽  
The Novel ◽  
Oil Film ◽  
Hydrodynamic Bearing ◽  
Damping Coefficients ◽  
Stiffness And Damping ◽  
Film Stiffness ◽  
Novel Design

This paper describes a combined theoretical and experimental investigation of the eight oil film stiffness and damping coefficients for a novel low impedance hydrodynamic bearing. The novel design incorporates a recess in the bearing surface which is connected to a standard commercial gas bag accumulator; this arrangement reduces the oil film dynamic stiffness and leads to improved machine response and stability. A finite difference method was used to solve Reynolds equation and yield the pressure distribution in the bearing oil film. Integration of the pressure profile then enabled the fluid film forces to be evaluated. A perturbation technique was used to determine the dynamic pressure components, and hence to determine the eight oil film stiffness and damping coefficients. Experimental data was obtained from a laboratory test rig in which a test bearing, floating on a rotating shaft, was excited by a multi-frequency force signal. Measurements of the resulting relative movement between bearing and journal enabled the oil film coefficients to be measured. The results of the work show good agreement between theoretical and experimental data, and indicate that the oil film impedance of the novel design is considerably lower than that of a conventional bearing.

scholarly journals A novel flexible tool with rotary ultrasonic spindle for fine grinding of tungsten carbide

2018 ◽  
Vol 185 ◽  
pp. 00018
Author(s):  
Albert Wen-Jeng Hsue ◽  
Yi-Zhong Zheng
Keyword(s):  
Tungsten Carbide ◽  
The Novel ◽  
Machining Processes ◽  
Flexible Tool ◽  
Operational Conditions ◽  
Cnc Grinding ◽  
Grinding Conditions ◽  
Novel Design ◽  
Conventional Machining ◽  
Tungsten Steel

Tungsten carbide is a typical difficult-to-cut material by conventional machining processes. In this paper, a novel design of flexible abrasives tool combined with a rotary ultrasonic machining (RUM) spindle is conducted to reduce the labor force significantly. The newly designed flexibility of tool-tip is aimed at preventing overcutting from the CNC grinding. The grinding conditions with resulted surface morphology of the tungsten steel were investigated through Taguchi design of experiment and ANOVA analysis. The machining capability of the novel flexible tool is compared with conventional tools through specific grinding paths under proper operational conditions.

Why Do So Few Consumers Use Health Care Quality Report Cards? A Framework for Understanding the Limited Consumer Impact of Comparative Quality Information

2018 ◽  
Vol 76 (5) ◽  
pp. 515-537 ◽  
Author(s):  
Neeraj Bhandari ◽  
Dennis P. Scanlon ◽  
Yunfeng Shi ◽  
Rachel A. Smith
Keyword(s):  
Health Care Quality ◽  
Care Quality ◽  
Report Cards ◽  
Quality Information ◽  
The Novel ◽  
Cognitive Limitations ◽  
Provider Quality ◽  
The Media ◽  
New Generation ◽  
Novel Design

Despite growing investment in producing and releasing comparative provider quality information (CQI), consumer use of CQI has remained poor. We offer a framework to interpret and synthesize the existing literature’s diverse approaches to explaining the CQI’s low appeal for consumers. Our framework cautions CQI stakeholders against forming unrealistic expectations of pervasive consumer use and suggests that they focus their efforts more narrowly on consumers who may find CQI more salient for choosing providers. We review the consumer impact of stakeholder efforts to apply the burgeoning knowledge of consumers’ cognitive limitations to the design and dissemination of the new generation of report cards; we conclude that while it is too limited to draw firm conclusions, early evidence suggests consumers are responding to the novel design and dissemination strategies. We find that consumers continue to have difficulty accessing reliable report cards, while the media remains underused in the dissemination of report cards.

scholarly journals Translucent Answer Predictions in Multi-Hop Reading Comprehension

2020 ◽  
Vol 34 (05) ◽  
pp. 7700-7707
Author(s):  
G P Shrivatsa Bhargav ◽  
Michael Glass ◽  
Dinesh Garg ◽  
Shirish Shevade ◽  
Saswati Dana ◽  
...  
Keyword(s):  
Reading Comprehension ◽  
Question Answering ◽  
State Of The Art ◽  
Local Context ◽  
The Novel ◽  
Loose Coupling ◽  
Loosely Coupled ◽  
Neural Architecture ◽  
Coupled Networks ◽  
Novel Design

Research on the task of Reading Comprehension style Question Answering (RCQA) has gained momentum in recent years due to the emergence of human annotated datasets and associated leaderboards, for example CoQA, HotpotQA, SQuAD, TriviaQA, etc. While state-of-the-art has advanced considerably, there is still ample opportunity to advance it further on some important variants of the RCQA task. In this paper, we propose a novel deep neural architecture, called TAP (Translucent Answer Prediction), to identify answers and evidence (in the form of supporting facts) in an RCQA task requiring multi-hop reasoning. TAP comprises two loosely coupled networks – Local and Global Interaction eXtractor (LoGIX) and Answer Predictor (AP). LoGIX predicts supporting facts, whereas AP consumes these predicted supporting facts to predict the answer span. The novel design of LoGIX is inspired by two key design desiderata – local context and global interaction– that we identified by analyzing examples of multi-hop RCQA task. The loose coupling between LoGIX and the AP reveals the set of sentences used by the AP in predicting an answer. Therefore, answer predictions of TAP can be interpreted in a translucent manner. TAP offers state-of-the-art performance on the HotpotQA (Yang et al. 2018) dataset – an apt dataset for multi-hop RCQA task – as it occupies Rank-1 on its leaderboard (https://hotpotqa.github.io/) at the time of submission.

scholarly journals Vibration-based tool life monitoring for ceramics micro-cutting under various toolpath strategies

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 125
Author(s):  
Zsolt János Viharos ◽  
László Móricz ◽  
Máté István Büki
Keyword(s):  
Tool Path ◽  
High Efficiency ◽  
Vibration Signal ◽  
Ceramic Materials ◽  
Micro Milling ◽  
The Novel ◽  
Feature Selection Technique ◽  
Tool Condition ◽  
Signal Features ◽  
Milling Tool

The 21st century manufacturing technology is unimagined without the various CAM (Computer Aided Manufacturing) toolpath generation programs. The aims of developing the toolpath strategies which are offered by the cutting control software is to ensure the longest possible tool lifetime and high efficiency of the cutting method. In this paper, the goal is to compare the efficiency of the 3 types of tool path strategies in the very special field of micro-milling of ceramic materials. The dimensional distortion of the manufactured geometries served to draw the Taylor curve for describing the wearing progress of the cutting tool helping to determine the worn-in, normal and wear out stages. These isolations allow to separate the connected high-frequency vibration measurements as well. Applying the novel feature selection technique of the authors, the basis for the vibration based micro-milling tool condition monitoring for ceramics cutting is presented for different toolpath strategies. It resulted in the identification of the most relevant vibration signal features and the presentation of the identified and automatically separated tool wearing stages as well.

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