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Zhou Y, Yuan J, Cavazzini G, Fu Y, Gao Q. The comparative transient prediction on hydrodynamic characteristics and flow field properties of pump-jets with accelerating and decelerating ducts. Sci Rep 2024; 14:5189. [PMID: 38431670 PMCID: PMC10908867 DOI: 10.1038/s41598-024-54388-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 02/12/2024] [Indexed: 03/05/2024] Open
Abstract
Pump-jet holds a pivotal position in various marine applications, underscoring the need for comprehending their transient behavior for the purpose of design enhancement and performance refinement. This paper employs Reynolds-averaged Navier-Stokes equations method in conjunction with Detached Eddy Simulation model. The study delves into the ramifications of accelerating and decelerating ducts, distinguished by camber f and attack angles α, on transient hydrodynamic characteristics. The hydrodynamic characteristics are investigated numerically, after the validation of the numerical methodology by comparing simulation outcomes against experimental results. Subsequently, the study delves into propulsion characteristics, followed by an exploration of time-domain and frequency-domain data transformed through fast Fourier transform to analyze thrust fluctuations and pulsating pressures. Additionally, a detailed examination of pressure distribution and velocity field is provided, aiming to dissect the mechanisms through the variations in f and α influence the flow field. Findings suggest that the outlet velocity of accelerating ducts significantly surpasses the inlet velocity, a behavior contrasted by decelerating ducts. Notably, the patterns of accelerating and decelerating ducts resulting from alterations in f exhibit consistent characteristics with those brought about by changes in α. However, several opposite characteristics surface in transient flow field due to the distinct modifications in the duct profile. Furthermore, by considering vorticity magnitude distribution and vortices, a comparative analysis elucidates the effects of varying f and α on rotor and stator trailing vortices. This contributes to understanding the flow instability mechanism under differing duct configurations. It is evident that changes in f and α exert significant influence on both performance and flow field.
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Affiliation(s)
- Yunkai Zhou
- National Research Center of Pumps, Jiangsu University, Zhenjiang, 212013, China
- Department of Industrial Engineering, University of Padua, Via Venezia 1, 35131, Padua, Italy
| | - Jianping Yuan
- National Research Center of Pumps, Jiangsu University, Zhenjiang, 212013, China
- Institute of Fluid Engineering Equipment, JITRI, Jiangsu University, Zhenjiang, 212013, China
| | - Giovanna Cavazzini
- Department of Industrial Engineering, University of Padua, Via Venezia 1, 35131, Padua, Italy
| | - Yanxia Fu
- National Research Center of Pumps, Jiangsu University, Zhenjiang, 212013, China.
- School of Energy and Power Engineering, Jiangsu University, Zhenjiang, 212013, China.
| | - Quanlin Gao
- National Research Center of Pumps, Jiangsu University, Zhenjiang, 212013, China
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Saisho H, Geisler I, Scharfschwerdt M, Sadat N, Zhang X, Puehler T, Ensminger S, Fujita B, Aboud A. Ex vivo evaluation of 3 different right ventricular outflow tract substitutes. Eur J Cardiothorac Surg 2024; 65:ezae081. [PMID: 38479833 DOI: 10.1093/ejcts/ezae081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 02/22/2024] [Indexed: 03/22/2024] Open
Abstract
OBJECTIVES The Ross procedure represents an excellent treatment option in younger patients with aortic stenosis but is limited by poor availability of homografts. In this study, we investigated the hydrodynamic performance of 3 different types of right ventricular outflow tract replacement with pericardium or synthetic material. METHODS Three different types of valved conduits were constructed using pericardium and/or synthetic material (Group PEPE: pericardial cusps and pericardial conduit, Group PEPR: pericardial cusps and Dacron conduit, Group PRPR: expanded polytetrafluoroethylene cusps and Dacron conduit). The conduits were designed according to the Ozaki method. Their hydrodynamic performance (effective orifice area, mean pressure gradient and leakage volume) were evaluated in a mock circulation loop at different hydrodynamic conditions. RESULTS Hydrodynamic assessment showed significantly larger effective orifice area of PEPE and PEPR compared to PRPR under all conditions and there were no significant differences between PEPE and PEPR [for condition 2: PEPE 2.43 (2.35-2.54) cm2, PEPR: 2.42 (2.4-2.5) cm2, PRPR: 2.08 (1.97-2.21) cm2, adjusted pairwise comparisons: PEPE versus PEPR: P = 0.80, PEPE versus PRPR: P < 0.001, PEPR versus PRPR: P < 0.001]. Mean pressure gradient was significantly lower for PEPE and PEPR compared with PRPR, whereas no significant differences were seen between PEPE and PEPR. Leakage volume was significantly lower for PEPE and PEPR compared with PRPR under all conditions while leakage was similar between PEPE and PEPR. CONCLUSIONS Pulmonary graft reconstruction with pericardium cusps showed superior hydrodynamic performance compared with polytetrafluoroethylene cusps. Our results suggest that it could be considered as an alternative substitute for right ventricular outflow tract replacement during the Ross procedure.
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Affiliation(s)
- Hiroyuki Saisho
- Department of Cardiac and Thoracic Vascular Surgery, University Hospital of Schleswig Holstein, Lübeck, Germany
| | - Ioana Geisler
- Department of Cardiac and Thoracic Vascular Surgery, University Hospital of Schleswig Holstein, Lübeck, Germany
| | - Michael Scharfschwerdt
- Department of Cardiac and Thoracic Vascular Surgery, University Hospital of Schleswig Holstein, Lübeck, Germany
| | - Najla Sadat
- Department of Cardiac and Thoracic Vascular Surgery, University Hospital of Schleswig Holstein, Lübeck, Germany
| | - Xiling Zhang
- Department of Cardiac and Thoracic Vascular Surgery, University Hospital of Schleswig Holstein, Lübeck, Germany
| | - Thomas Puehler
- Department of Cardiac and Thoracic Vascular Surgery, University Hospital of Schleswig Holstein, Lübeck, Germany
- DZHK (German Center for cardiovascular research), Partner Site Hamburg/Kiel/Luebeck, Germany
| | - Stephan Ensminger
- Department of Cardiac and Thoracic Vascular Surgery, University Hospital of Schleswig Holstein, Lübeck, Germany
- DZHK (German Center for cardiovascular research), Partner Site Hamburg/Kiel/Luebeck, Germany
| | - Buntaro Fujita
- Department of Cardiac and Thoracic Vascular Surgery, University Hospital of Schleswig Holstein, Lübeck, Germany
- DZHK (German Center for cardiovascular research), Partner Site Hamburg/Kiel/Luebeck, Germany
| | - Anas Aboud
- Department of Cardiac and Thoracic Vascular Surgery, University Hospital of Schleswig Holstein, Lübeck, Germany
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Xue C, Chen Y, Zhu B, Wang X. A comparative study of structural parameters for spiral groove bearing in centrifugal rotary blood pump. Heliyon 2023; 9:e14313. [PMID: 36942254 PMCID: PMC10023960 DOI: 10.1016/j.heliyon.2023.e14313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 02/26/2023] [Accepted: 02/28/2023] [Indexed: 03/08/2023] Open
Abstract
In this work, the hydrodynamic characteristics of spiral groove bearing in centrifugal rotary blood pump is investigated for the cases with different structural parameters. The simulation model is proposed based on the CFD technology and the effectiveness of simulation model is demonstrated by the published data. Then, the pressure, load carrying capacity and friction torque are calculated and the characteristics of pressure distribution are analyzed. It is found that the structural parameters of spiral groove would lead to the complex pressure distribution of blood film and the load carrying capacity also changes at the same time. Moreover, the deep analysis of structural characteristics for spiral groove bearing is conducted based on the orthogonal design method, which could improve the computational efficiency of hydrodynamic behavior of spiral groove bearing. And, the mapping relationship between structural parameter and hydrodynamic performance of bearing preferably is also illustrated.
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Affiliation(s)
- Cong Xue
- Department of Cardiology, The Third Affiliated Hospital of Soochow University, Changzhou 213003, China
- Corresponding author.
| | - Yu Chen
- School of Mechanical Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Bin Zhu
- Department of Critical Care Medicine, The Third Affiliated Hospital of Soochow University, Changzhou 213003, China
| | - Xiuying Wang
- School of Mechanical Engineering, Jiangsu University of Technology, Changzhou 213001, China
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Di Leonardo S, Vella D, Grillo CS, Martorana C, Torre S, Argano V, Burriesci G. Hydrodynamic ex vivo analysis of valve sparing techniques: assessment and comparison. Eur J Cardiothorac Surg 2023; 63:7028489. [PMID: 36744913 PMCID: PMC10049755 DOI: 10.1093/ejcts/ezad040] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 01/23/2023] [Accepted: 02/03/2023] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVES Valve-sparing procedures are surgical techniques allowing to restore adequate function of the native aortic valve by replacing the dysfunctional ascending aorta with a prosthetic conduit. A number of techniques are currently used, such as Yacoub's remodelling and David's reimplantation, based on a regular straight conduit. More recently, the De Paulis proposed the use of bulging conduits to reconstruct the shape of the Valsalva sinuses. This work investigates the impact of the valve-sparing technique on the aortic valve function. METHODS The performance of three porcine aortic roots (Medtronic Freestyle™) was assessed in a cardiovascular pulse duplicator before and after performing three alternative valve-sparing procedures: David's reimplantation, Yacoub's remodelling and De Paulis' reimplantation. RESULTS The porcine aortic roots, representative of the healthy native configuration, were characterised by the highest efficiency, with a mean energetic dissipation under normal operating conditions of 26 mJ. David's and Yacoub's techniques resulted in significantly lower performance (with mean energetic loss of about 70 mJ for both cases). The De Paulis' procedure exhibited intermediate behaviour, with superior systolic performance and valve dynamics similar to the native case, and a mean energetic loss of 38 mJ. CONCLUSIONS The dynamics and performance after valve-sparing strongly depend on the adopted technique, with the use of conduits replicating the presence of Valsalva sinuses restoring more physiological conditions.
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Affiliation(s)
| | - Danila Vella
- Bioengineering Group, Ri.MED Foundation, Palermo, Italy
| | | | - Carla Martorana
- School of Medicine and Surgery, University of Palermo, Italy
| | - Salvatore Torre
- School of Medicine and Surgery, University of Palermo, Italy.,Cardiac Surgery Unit, Policlinico Paolo Giaccone, University of Palermo, Italy
| | - Vincenzo Argano
- School of Medicine and Surgery, University of Palermo, Italy.,Cardiac Surgery Unit, Policlinico Paolo Giaccone, University of Palermo, Italy
| | - Gaetano Burriesci
- Bioengineering Group, Ri.MED Foundation, Palermo, Italy.,UCL Mechanical Engineering, University College London, UK
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Wang R, Wei B, Zhu J, Zhao X, Yu G. Study on the hydrodynamic performance and treatment effect of a modified biological carrier in wastewater treatment. Sci Total Environ 2022; 844:156974. [PMID: 35764159 DOI: 10.1016/j.scitotenv.2022.156974] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 06/15/2022] [Accepted: 06/21/2022] [Indexed: 06/15/2023]
Abstract
A modified biological carrier used in the moving bed biofilm reactor was developed from the perspective of the constituent material and the structure, then its hydrodynamic performance and treatment effect in wastewater treatment were investigated, and the movement of the modified biological carriers was simulated by Flow 3D software. The results show that the specific surface area of the modified biological carrier prepared by mixing PA and HDPE materials is about 5.1 % higher than that of the existing biological carrier; the folded cylindrical structure is adopted, which makes the directions of the aeration and water flow though the interior of the modified biological carrier more deflected, and keeps the flushing and pushing with the flow all the time; the presence of the modified biological carriers plays a good role in the gas distribution, and a large number of vortices with different sizes are generated in the reactor, which enhances the mass transfer in the reactor; the average removal rate of COD is up to 88 %, and the maximum removal rate of NH3-N is up to 95 %, which indicates that the treat effect of the bioreactor is enhanced by the modified biological carriers. The modified biological carrier has the better hydrodynamic performance and treatment effect, which has the prospect of the popularization and application in the field of wastewater treatment.
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Affiliation(s)
- Rui Wang
- SKLOE, CISSE, School of Naval Architecture, Ocean & Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Bing Wei
- Guangxi Taineng Engineering Consulting Co. LTD, Guangxi 53000, China
| | - Jian Zhu
- Guangxi Taineng Engineering Consulting Co. LTD, Guangxi 53000, China
| | - Xudong Zhao
- SKLOE, CISSE, School of Naval Architecture, Ocean & Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Guoliang Yu
- SKLOE, CISSE, School of Naval Architecture, Ocean & Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
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Saisho H, Scharfschwerdt M, Schaller T, Reil JC, Ensminger S, Fujita B, Aboud A. An ex vivo evaluation of two different suture techniques for the Ozaki aortic neocuspidization procedure. Interact Cardiovasc Thorac Surg 2021; 33:518-524. [PMID: 34089604 DOI: 10.1093/icvts/ivab138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 03/11/2021] [Accepted: 03/31/2021] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES We investigated the Ozaki procedure using a single interrupted suture technique (SST) and compared this with the standard continuous suture technique (CST) with regard to hydrodynamic valve performance. In addition, both techniques were compared with the native aortic valve (NAV). METHODS Effective orifice area, mean pressure gradient and leakage volume were evaluated in the NAV as well as after an Ozaki procedure using SST or CST in fresh swine aortic roots using a mock circulation loop. The NAV, SST and CST were evaluated under 4 defined hydrodynamic conditions. RESULTS Both suture techniques resulted in a similar effective orifice area under all conditions [for stroke volume of 70 ml: SST: 1.50 (1.35-1.87) vs CST: 1.57 (1.41-1.72) cm2, P = 0.8] and there were no significant differences between both suture techniques and the NAV (P > 0.05). Regarding mean pressure gradient, the Ozaki procedure with SST and CST showed no significant differences [7.23 (5.53-8.91) vs 7.04 (6.65-7.60) mmHg, P = 0.72] and there was no significant difference between both suture techniques and the NAV (P > 0.1). In leakage volume, there was no significant difference between SST and CST [4.49 (3.91-4.99) vs CST: 4.23 (3.58-4.87) ml/stroke, P = 0.34]. CONCLUSIONS The Ozaki procedure with SST performed similarly to that with CST with regard to hydrodynamic performance. Our results suggest that the Ozaki procedure can be performed with SST instead of CST, which may be useful in patients with limited surgical exposure, such as a small annulus.
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Affiliation(s)
- Hiroyuki Saisho
- Department of Cardiac and Thoracic Vascular Surgery, University Hospital of Schleswig-Holstein, Lübeck, Germany.,University of Lübeck, Lübeck, Germany
| | - Michael Scharfschwerdt
- Department of Cardiac and Thoracic Vascular Surgery, University Hospital of Schleswig-Holstein, Lübeck, Germany.,University of Lübeck, Lübeck, Germany
| | - Tim Schaller
- Department of Cardiac and Thoracic Vascular Surgery, University Hospital of Schleswig-Holstein, Lübeck, Germany.,University of Lübeck, Lübeck, Germany
| | - Jan Christian Reil
- University of Lübeck, Lübeck, Germany.,Department of Medicine II, University Hospital of Schleswig-Holstein, Lübeck, Germany
| | - Stephan Ensminger
- Department of Cardiac and Thoracic Vascular Surgery, University Hospital of Schleswig-Holstein, Lübeck, Germany.,University of Lübeck, Lübeck, Germany
| | - Buntaro Fujita
- Department of Cardiac and Thoracic Vascular Surgery, University Hospital of Schleswig-Holstein, Lübeck, Germany.,University of Lübeck, Lübeck, Germany
| | - Anas Aboud
- Department of Cardiac and Thoracic Vascular Surgery, University Hospital of Schleswig-Holstein, Lübeck, Germany.,University of Lübeck, Lübeck, Germany
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Zhao Z, Xiao Q, Tchivelekete GM, Reilly J, Jiang H, Shu X. Quantification of computational fluid dynamics simulation assists the evaluation of protection by Gypenosides in a zebrafish pain model. Physiol Behav 2020; 229:113223. [PMID: 33127465 DOI: 10.1016/j.physbeh.2020.113223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 10/02/2020] [Accepted: 10/24/2020] [Indexed: 10/23/2022]
Abstract
In recent years, due to its rapid reproduction rate and the similarity of its genetic structure to that of human, the zebrafish has been widely used as a pain model to study chemical influences on behavior. Swimming behaviors are mediated by motoneurons in the spinal cord that drive muscle contractions, therefore a knowledge of internal muscle mechanics can assist the understanding of the effects of drugs on swimming activity. To demonstrate that the technique used in our study can supplement biological observations by quantifying the contribution of muscle effects to altered swimming behaviours, we have evaluated the pain/damage caused by 0.1% acetic acid to the muscle of 5 dpf zebrafish larvae and the effect of protection from this pain/damage with the saponin Gypenosides (GYP) extracted from Gynostemma pentaphyllum. We have quantified the parameters related to muscle such as muscle power and the resultant hydrodynamic force, proving that GYP could alleviate the detrimental effect of acetic acid on zebrafish larvae, in the form of alleviation from swimming debility, and that the muscle status could be quantified to represent the degree of muscle damage due to the acetic acid and the recovery due to GYP. We have also linked the behavioral changes to alteration of antioxidant and inflammation gene expression. The above results provide novel insights into the reasons for pain-related behavioral changes in fish larvae, especially from an internal muscle perspective, and have quantified these changes to help understand the protection of swimming behaviors and internal muscle by GYP from acetic acid-induced damage.
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Affiliation(s)
- Zhenkai Zhao
- Department of Naval Architecture, Ocean, and Marine Engineering, University of Strathclyde, Glasgow G4 0LZ, UK
| | - Qing Xiao
- Department of Naval Architecture, Ocean, and Marine Engineering, University of Strathclyde, Glasgow G4 0LZ, UK.
| | - Gabriel Mbuta Tchivelekete
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow G4 0BA, United Kingdom
| | - James Reilly
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow G4 0BA, United Kingdom
| | - Huirong Jiang
- Strathclyde Institute of Pharmacy and Biomedical Sciences, Glasgow G4 0RE, United Kingdom
| | - Xinhua Shu
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow G4 0BA, United Kingdom; Department of Vision Science, Glasgow Caledonian University, Glasgow G4 0BA, United Kingdom; School of Basic Medical Sciences, Shaoyang University, Shaoyang, Hunan 422000, P. R. China.
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Liu D, Xie Q, Huang X, Wan C, Deng F, Liang D, Liu J. Backwashing behavior and hydrodynamic performances of granular activated carbon blends. Environ Res 2020; 184:109302. [PMID: 32120125 DOI: 10.1016/j.envres.2020.109302] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Revised: 01/13/2020] [Accepted: 02/24/2020] [Indexed: 06/10/2023]
Abstract
Ozone-biological activated carbon (O3-BAC) process has been proved to be an efficient and cost-effective technology in advanced treatment of drinking water. However, O3-BAC raises strict requirements in adsorption, hydrodynamic and regeneration performances, which one single activated carbon could hardly all-sided meet. Blending activated carbons seems to be an appropriate and economically feasible method to deal with the issue. Thus, the uniformity and stability of activated carbon blends during water treatment, especially in backwashing process are of great importance. In this paper, cyclic experiments of downward adsorption and upward backwash on 11 typical commercial granular coal-based activated carbons and their blends were carried out in column test. Hydrodynamic performances such as bed expansion rate and bed pressure drop were measured. The uniformity and stability of activated carbon blends were investigated by determining iodine number of samples collected from different heights of activated carbon bed. Then, both traditional regression methods and back-propagation neural network model were utilized to predict superficial velocity at 30% bed expansion rate and maximum bed pressure drop of activated carbon blends. The results indicate that water backwashing process has no effect on the composition proportion of activated carbon blends, and slightly changes the particle distribution of activated carbon bed regarding pore structure and adsorption capacity. A three-layer back-propagation neural network model for superficial velocity at 30% bed expansion rate yields mean relative errors of 2.17%, which is much lower than that given by traditional regression methods such as 5.53% (weighted average), 4.08% (linear) and 4.06% (polynomial). Moreover, the back-propagation neural network model for maximum bed pressure drop yields mean relative errors of 1.37%, which is much lower than that given by traditional regression methods such as 4.31% (weighted average), 4.28% (linear) and 4.22% (polynomial). The non-linear relationships can be accurately identified by the back-propagation neural network model.
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Affiliation(s)
- Deqian Liu
- School of Chemical and Environmental Engineering, China University of Mining & Technology (Beijing), Beijing, 10083, China
| | - Qiang Xie
- School of Chemical and Environmental Engineering, China University of Mining & Technology (Beijing), Beijing, 10083, China.
| | - Xiaoqing Huang
- School of Chemical and Environmental Engineering, China University of Mining & Technology (Beijing), Beijing, 10083, China
| | - Chaoran Wan
- School of Chemical and Environmental Engineering, China University of Mining & Technology (Beijing), Beijing, 10083, China
| | - Feng Deng
- School of Chemical and Environmental Engineering, China University of Mining & Technology (Beijing), Beijing, 10083, China; The Coal Chemical Engineering Collaborative Innovation Center of Guizhou Province, Guizhou University of Engineering Science, Bijie, Guizhou, 551700, China
| | - Dingcheng Liang
- School of Chemical and Environmental Engineering, China University of Mining & Technology (Beijing), Beijing, 10083, China
| | - Jinchang Liu
- School of Chemical and Environmental Engineering, China University of Mining & Technology (Beijing), Beijing, 10083, China
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Liu W, Li N, Zhao J, Su Y. Wake structure and hydrodynamic performance of flapping foils mimicking fish fin kinematics. Saudi J Biol Sci 2017; 24:1344-1354. [PMID: 28855830 PMCID: PMC5562471 DOI: 10.1016/j.sjbs.2016.09.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Revised: 09/01/2016] [Accepted: 09/04/2016] [Indexed: 11/17/2022] Open
Abstract
Numerical simulations are used to investigate the wake structure and hydrodynamic performance of bionic flapping foils. The study is motivated by the quest to understand the fluid dynamics of fish fins and use it in the underwater propulsion. The simulations employ an immersed boundary method that makes it possible to simulate flows with complex moving boundaries on fixed Cartesian grids. A detailed analysis of the vortex topology shows that the wake of flapping foils is dominated by two sets of complex shaped vortex rings that convect at oblique angles to the wake centerline. The wake of these flapping foils is characterized by two oblique jets. Simulations are also used to examine the wake vortex and hydrodynamic performance over a range of Strouhal numbers and maximum pitch angles and the connection between the foil kinematics, vortex dynamics and force production is discussed. The results show that the variety law of the hydrodynamic performance with kinematic parameters strongly depends on the flow dynamics underlying the force production, including the orientation, interconnection and dissipation rate of the vortex rings.
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Affiliation(s)
- Weixing Liu
- Science and Technology on Underwater Vehicle Laboratory, Harbin Engineering University, Harbin 150001, China
| | - Ningyu Li
- Science and Technology on Underwater Vehicle Laboratory, Harbin Engineering University, Harbin 150001, China
- Corresponding author.
| | - Jinxin Zhao
- Beijing Machine and Equipment Institute, Beijing 100854, China
| | - Yumin Su
- Science and Technology on Underwater Vehicle Laboratory, Harbin Engineering University, Harbin 150001, China
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10
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Miller P, Narazaki T, Isojunno S, Aoki K, Smout S, Sato K. Body density and diving gas volume of the northern bottlenose whale (Hyperoodon ampullatus). ACTA ACUST UNITED AC 2016; 219:2458-68. [PMID: 27296044 PMCID: PMC5004977 DOI: 10.1242/jeb.137349] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 05/31/2016] [Indexed: 11/27/2022]
Abstract
Diving lung volume and tissue density, reflecting lipid store volume, are important physiological parameters that have only been estimated for a few breath-hold diving species. We fitted 12 northern bottlenose whales with data loggers that recorded depth, 3-axis acceleration and speed either with a fly-wheel or from change of depth corrected by pitch angle. We fitted measured values of the change in speed during 5 s descent and ascent glides to a hydrodynamic model of drag and buoyancy forces using a Bayesian estimation framework. The resulting estimate of diving gas volume was 27.4±4.2 (95% credible interval, CI) ml kg−1, closely matching the measured lung capacity of the species. Dive-by-dive variation in gas volume did not correlate with dive depth or duration. Estimated body densities of individuals ranged from 1028.4 to 1033.9 kg m−3 at the sea surface, indicating overall negative tissue buoyancy of this species in seawater. Body density estimates were highly precise with ±95% CI ranging from 0.1 to 0.4 kg m−3, which would equate to a precision of <0.5% of lipid content based upon extrapolation from the elephant seal. Six whales tagged near Jan Mayen (Norway, 71°N) had lower body density and were closer to neutral buoyancy than six whales tagged in the Gully (Nova Scotia, Canada, 44°N), a difference that was consistent with the amount of gliding observed during ascent versus descent phases in these animals. Implementation of this approach using longer-duration tags could be used to track longitudinal changes in body density and lipid store body condition of free-ranging cetaceans. Summary: Body density and diving gas volume, two important but poorly understood physiological characteristics of beaked whales, are revealed through analysis of hydrodynamic performance during glides.
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Affiliation(s)
- Patrick Miller
- Sea Mammal Research Unit, University of St Andrews, St Andrews, Fife KY16 9QQ, UK Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
| | - Tomoko Narazaki
- Sea Mammal Research Unit, University of St Andrews, St Andrews, Fife KY16 9QQ, UK Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
| | - Saana Isojunno
- Sea Mammal Research Unit, University of St Andrews, St Andrews, Fife KY16 9QQ, UK
| | - Kagari Aoki
- Sea Mammal Research Unit, University of St Andrews, St Andrews, Fife KY16 9QQ, UK Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
| | - Sophie Smout
- Sea Mammal Research Unit, University of St Andrews, St Andrews, Fife KY16 9QQ, UK
| | - Katsufumi Sato
- Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
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