Innovative Research and Applications in Hydrodynamics and Flow Control, 2nd Edition

A special issue of Inventions (ISSN 2411-5134). This special issue belongs to the section "Inventions and Innovation in Energy and Thermal/Fluidic Science".

Deadline for manuscript submissions: 31 August 2024 | Viewed by 8256

Special Issue Editors


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Guest Editor
School of Marine Science and Technology, Northwestern Polytechnical University, 127 Youyi Road, Beilin, Xi’an 710072, China
Interests: drag reduction; flow control; marine engineering
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
School of Marine Science and Technology, Northwestern Polytechnical University, 127 Youyi Road, Beilin, Xi’an 710072, China
Interests: multiphase flow; bubbles; Lattice Boltzmann Method
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

This Special Issue aims to collect cutting-edge developments in the area of hydrodynamics and flow control, including both fundamental and engineering research. Hydrodynamics is of great importance in ships, marine engineering, energy, etc. It influences the kinetics and kinematics of ships, underwater vehicles, and marine structures. Flow control techniques can be used to manipulate hydrodynamics for saving energy, high performance, etc. Topics of interest include, but are not limited to:

  1. Design of ships, underwater vehicles, and marine structures;
  2. Shape optimization of marine vehicles;
  3. Experimental fluid mechanics of marine structures;
  4. Computational methods for fluids;
  5. Applications of CFD methods;
  6. Flow control techniques;
  7. Fluid mechanics;
  8. Machine learning methods for fluids.

Also, feel free to browse the very interesting papers published in the first Edition "Innovative Research and Applications in Hydrodynamics and Flow Control".

Dr. Peng Du
Prof. Dr. Haibao Hu
Prof. Dr. Xiaopeng Chen
Guest Editors

Manuscript Submission Information

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Keywords

  • hydrodynamics
  • flow control
  • fluid mechanics
  • CFD

Published Papers (8 papers)

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Research

23 pages, 11190 KiB  
Article
Numerical Simulation of Effective Heat Recapture Ammonia Pyrolysis System for Hydrogen Energy
by Jian Tiong Lim, Eddie Yin-Kwee Ng, Hamid Saeedipour and Hiang Kwee Lee
Inventions 2024, 9(3), 56; https://doi.org/10.3390/inventions9030056 - 10 May 2024
Viewed by 585
Abstract
This paper proposes a solution to address the challenges of high storage and transport costs associated with using hydrogen (H2) as an energy source. It suggests utilizing ammonia (NH3) as a hydrogen carrier to produce [...] Read more.
This paper proposes a solution to address the challenges of high storage and transport costs associated with using hydrogen (H2) as an energy source. It suggests utilizing ammonia (NH3) as a hydrogen carrier to produce H2 onsite for hydrogen gas turbines. NH3 offers higher volumetric hydrogen density compared to liquid H2, potentially reducing shipping costs by 40%. The process involves NH3 pyrolysis, which utilizes the heat waste from exhaust gas generated by gas turbines to produce H2 and nitrogen (N2). Numerical simulations were conducted to design and understand the behaviour of the heat recapture NH3 decomposition system. The design considerations included the concept of the number of transfer units and heat exchanger efficiency, achieving a heat recapture system efficiency of up to 91%. The simulation of NH3 decomposition was performed using ANSYS, a commercial simulation software, considering wall surface reactions, turbulent flow, and chemical reaction. Parameters such as activation energy and pre-exponential factor were provided by a study utilizing a nickel wire for NH3 decomposition experiments. The conversion of NH3 reached up to 94% via a nickel-based catalyst within a temperature range of 823 K to 923 K which is the exhaust gas temperature range. Various factors were considered to compare the efficiency of the system, including the mass flow of NH3, operating gauge pressure, mass flow of exhaust gas, among others. Result showed that pressure would not affect the conversion of NH3 at temperatures above 800 K, thus a lower amount of energy is required for a compression purpose in this approach. The conversion is maintained at 94% to 97% when lower activation energy is applied via a ruthenium-based catalyst. Overall, this study showed the feasibility of utilizing convective heat transfer from exhaust gas in hydrogen production by NH3 pyrolysis, and this will further enhance the development of NH3 as the potential H2 carrier for onsite production in hydrogen power generation. Full article
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9 pages, 2588 KiB  
Article
Hydraulic Drilling Nozzle Design and Research
by Przemysław Toczek, Rafał Wiśniowski, Albert Złotkowski and Wojciech Teper
Inventions 2024, 9(3), 51; https://doi.org/10.3390/inventions9030051 - 29 Apr 2024
Viewed by 592
Abstract
In light of the European Union’s zero-emissions policy and the growing demand for energy associated with technological advances, it is necessary to consider adopting technologies and innovative solutions that simultaneously reduce greenhouse gas emissions while increasing potential extraction from existing hydrocarbon deposits, for [...] Read more.
In light of the European Union’s zero-emissions policy and the growing demand for energy associated with technological advances, it is necessary to consider adopting technologies and innovative solutions that simultaneously reduce greenhouse gas emissions while increasing potential extraction from existing hydrocarbon deposits, for example. This can result in increased production from deposits with low reservoir energy values or those in which the energy value does not allow the resource to be exploited on its own. By using a hydraulic drilling nozzle that harnesses the hydraulic energy of the fluid stream for workover, the possibility of increasing the contact between the reservoir layer and the producing well increases in direct proportion to the number of small-diameter radial wells drilled with a hydraulic rotary head from a horizontal well toward the reservoir layer. The main aspect of this paper is to outline an algorithm for the design of rotary drilling heads to maximize the use of the hydraulic energy from fluid streams flowing from the face of innovative drilling tools. The presented design algorithm allows changing the mutual position between the holes in the face section and the angle of the holes with respect to the longitudinal axis of the designed hydraulic rotary nozzle, simplifying the design work. The use of the rotary head developed using this algorithm enables seamless drilling in rocks with compressive strength Rc = 50 MPa, considering the drilling progress at ROP = 4 mm/s. Full article
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15 pages, 4348 KiB  
Article
Improving the Hydrodynamic Performance of Underwater Tags for Blue Shark Monitoring
by José Azevedo, Violeta Carvalho, Tiago Bartolomeu, Ana Arieira, Senhorinha F. Teixeira and José C. Teixeira
Inventions 2024, 9(3), 48; https://doi.org/10.3390/inventions9030048 - 26 Apr 2024
Viewed by 685
Abstract
The use of tag devices in marine environments has become indispensable in attaining a better understanding of marine life and contributing to conservation efforts. However, the successful deployment and operation of underwater tags both depend significantly on their hydrodynamic characteristics, particularly their resistance [...] Read more.
The use of tag devices in marine environments has become indispensable in attaining a better understanding of marine life and contributing to conservation efforts. However, the successful deployment and operation of underwater tags both depend significantly on their hydrodynamic characteristics, particularly their resistance to motion and stability in various environmental conditions. Herein, a comprehensive study on the hydrodynamic characteristics and optimization of an underwater tag designed for monitoring blue sharks is presented. Firstly, a validation process is conducted by comparing the computational fluid dynamics (CFD) results with the experimental data from Myring’s study, focusing on the resistance characteristics of the tag’s body and the impact of various operational conditions. Subsequently, the validated CFD model is applied to assess the hydrodynamic performance of the tag under different flow conditions, velocities, and angles of attack. Through iterative simulations, including mesh independence studies and boundary condition adjustments, the study identifies key parameters influencing the tag’s resistance and stability. Furthermore, the paper proposes and implements design modifications, including the incorporation of stabilizing fins, aimed at minimizing resistance and improving the tag’s equilibrium position. The effectiveness of these design enhancements is demonstrated through a comparative analysis of resistance and pitching moments for both preliminary and optimized tag configurations. Overall, the study provides valuable insights into the hydrodynamic behavior of underwater tags and offers practical recommendations for optimizing their design to minimize interference with the movement of tagged marine animals. Full article
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27 pages, 7550 KiB  
Article
The Expected Dynamics for the Extreme Wind and Wave Conditions at the Mouths of the Danube River in Connection with the Navigation Hazards
by Alina Beatrice Răileanu, Liliana Rusu, Andra Marcu and Eugen Rusu
Inventions 2024, 9(2), 41; https://doi.org/10.3390/inventions9020041 - 12 Apr 2024
Viewed by 1527
Abstract
The entrance in the Sulina channel in the Black Sea is the target area of this study. This represents the southern gate of the seventh Pan-European transport corridor, and it is usually subjected to high navigation traffic. The main objective of the work [...] Read more.
The entrance in the Sulina channel in the Black Sea is the target area of this study. This represents the southern gate of the seventh Pan-European transport corridor, and it is usually subjected to high navigation traffic. The main objective of the work is to provide a more comprehensive picture concerning the past and future expected dynamics of the environmental matrix in this coastal area, including especially the extreme wind and wave conditions in connection with the possible navigation risks. The methodology considered assumes analyses performed at three different levels. First, an analysis of some in situ measurements at the zero-kilometer point of the Danube is carried out for the 15-year period of 2009–2023. Together with the maximum wind speed and the maximum value of the wind gusts, the water level variation was analyzed at this point. As a second step, the analysis is based on wind speed data provided by regional climate models. Two periods, each spanning 30 years, are considered. These are the recent past (1976–2005), when comparisons with ERA5 reanalysis data were also performed, and the near future (2041–2070), when two different models and three climate scenarios were considered. The focus was on the extreme wind speed values, performing comparisons between the past and future expected extreme winds. Finally, the third analysis is related to the wave conditions. Thus, using as a forcing factor each of the wind fields that was previously analyzed, simulations employing a spectral wave model were carried out. The wave modeling system was focused using three different computational domains with increasing resolution towards the target area, and the nearshore wave conditions were evaluated. The results show that both the extreme wind and wave conditions are expected to slightly increase in the future. Especially in the wintertime, strong wind fields are often expected in this area, with wind gusts exceeding more than 70% of the hourly average wind velocity. With regard to the waves, due to the complex nearshore phenomena, considerable enhancements in terms of significant wave heights are induced, and there is also an elevated risk of the occurrence of rogue waves. This work is still ongoing, and taking into account the high navigation risks highlighted, the next step would be to elaborate the risk assessment of severe shipping conditions, particularly related to the likelihood or probability of adverse conditions with the potential of generating hazardous situations in this coastal environment. Full article
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21 pages, 473 KiB  
Article
The Basic k-ϵ Model and a New Model Based on General Statistical Descriptions of Anisotropic Inhomogeneous Turbulence Compared with DNS of Channel Flow at High Reynolds Number
by J. J. H. Brouwers
Inventions 2024, 9(2), 38; https://doi.org/10.3390/inventions9020038 - 8 Apr 2024
Viewed by 853
Abstract
Predictions are presented of mean values of statistical variables of large-scale turbulent flow of the widely used basic k-ϵ model, and of a new model, which is based on general statistical descriptions of turbulence. The predictions are verified against published results [...] Read more.
Predictions are presented of mean values of statistical variables of large-scale turbulent flow of the widely used basic k-ϵ model, and of a new model, which is based on general statistical descriptions of turbulence. The predictions are verified against published results of direct numerical simulations (DNSs) of Navier–Stokes equations. The verification concerns turbulent channel flow at shear Reynolds numbers of 950, 2000, and 104. The basic k-ϵ model is largely based on empirical formulations accompanied by calibration constants. This contrasts with the new model, where descriptions of leading statistical quantities are based on the general principles of statistical turbulence at a large Reynolds number and stochastic theory. Predicted values of major output variables such as turbulent viscosity, diffusivity of passive admixture, temperature, and fluid velocities compare well with DNS for the new model. Significant differences are seen for the basic k-ϵ model. Full article
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19 pages, 30801 KiB  
Article
Numerical Study of the Gas–Solid Separation Performance of Axial Flow Cyclone Separators
by Yanqin Mao, Roman Chertovskih and Liang Cai
Inventions 2024, 9(2), 34; https://doi.org/10.3390/inventions9020034 - 22 Mar 2024
Viewed by 1040
Abstract
Cyclone separators, which have a high separation performance, play a crucial role in mitigating the occurrence of dust explosion incidents. This study aims to improve the performance of an axial cyclone separator using the results of simulations employing the [...] Read more.
Cyclone separators, which have a high separation performance, play a crucial role in mitigating the occurrence of dust explosion incidents. This study aims to improve the performance of an axial cyclone separator using the results of simulations employing the RNG k-ε model together with a user-defined function to simulate the wall collision process. The effectiveness of various structural modifications to the vortex tube has been addressed. Specifically, we found that increasing the number of blades, reducing the blade exit angle, and adopting L-shaped blades increase separation efficiency. Additionally, enlarging the guide vane and exhaust pipe diameters, as well as increasing the exhaust pipe inclination angle, contribute to an improved separation performance due to the developed tangential velocity and vortex cores. However, it also increases the pressure drop losses due to the increase in the turbulence pulsation entropy and the wall entropy, while the time-averaged entropy is found to be less significant. As a result, our study sheds light on the flow characteristics, the gas–solid separation process, and the energy loss mechanism in the cyclone separator. Full article
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20 pages, 5496 KiB  
Article
Modeling and Optimization of Interior Ballistics within Pneumatic Underwater Launchers
by Haixia Gong, Zhuoran Ping, Fance Meng and Shuping Hou
Inventions 2024, 9(2), 30; https://doi.org/10.3390/inventions9020030 - 8 Mar 2024
Viewed by 1003
Abstract
A new area of underwater equipment research focus is the use of underwater unmanned vehicles (UUVs) with launch mechanisms to deploy lightweight and small-sized robots for functions including communication, exploration, and detection. The internal ballistic mathematical model of the underwater launch system for [...] Read more.
A new area of underwater equipment research focus is the use of underwater unmanned vehicles (UUVs) with launch mechanisms to deploy lightweight and small-sized robots for functions including communication, exploration, and detection. The internal ballistic mathematical model of the underwater launch system for small robots is established in this paper. The internal ballistic parameters and the robot displacement and velocity change rule over time are obtained. The optimization calculation of the crucial parameters to be determined by the particle swarm algorithm is completed. Following optimization, the gas cylinder’s initial pressure is 2 MPa, its capacity is 30 L, its opening area is 9.683 × 10−5 m2, and its opening time is 0.02 s. A numerical simulation is performed for the small robot’s underwater launch process, based on the mathematical and physical model supplied by Fluent 2020 software. The results yield the robot’s motion law and the properties of the flow field during the launch process. The purpose of the underwater launcher experiment is to determine the robot’s motion characteristics. The accuracy of the theoretical model is confirmed by comparing and analyzing the numerical simulation results with the actual data. Full article
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16 pages, 7857 KiB  
Article
From Sparse to Dense Representations in Open Channel Flow Images with Convolutional Neural Networks
by Filippos Sofos, George Sofiadis, Efstathios Chatzoglou, Apostolos Palasis, Theodoros E. Karakasidis and Antonios Liakopoulos
Inventions 2024, 9(2), 27; https://doi.org/10.3390/inventions9020027 - 4 Mar 2024
Viewed by 1259
Abstract
Convolutional neural networks (CNN) have been widely adopted in fluid dynamics investigations over the past few years due to their ability to extract and process fluid flow field characteristics. Both in sparse-grid simulations and sensor-based experimental data, the establishment of a dense flow [...] Read more.
Convolutional neural networks (CNN) have been widely adopted in fluid dynamics investigations over the past few years due to their ability to extract and process fluid flow field characteristics. Both in sparse-grid simulations and sensor-based experimental data, the establishment of a dense flow field that embeds all spatial and temporal flow information is an open question, especially in the case of turbulent flows. In this paper, a deep learning (DL) method based on computational CNN layers is presented, focusing on reconstructing turbulent open channel flow fields of various resolutions. Starting from couples of images with low/high resolution, we train our DL model to efficiently reconstruct the velocity field of consecutive low-resolution data, which comes from a sparse-grid Direct Numerical Simulation (DNS), and focus on obtaining the accuracy of a respective dense-grid DNS. The reconstruction is assessed on the peak signal-to-noise ratio (PSNR), which is found to be high even in cases where the ground truth input is scaled down to 25 times. Full article
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