Article
Mechanics
Akhil Nekkanti, Sheel Nidhan, Oliver T. Schmidt, Sutanu Sarkar
Summary: This study investigates a turbulent circular disk wake database and identifies the presence of large-scale streaks in the wake, as well as characterizes the lift-up mechanism involved in streak formation. It is the first study to report and characterize large-scale low-frequency streaks and their associated lift-up mechanism in a turbulent wake.
JOURNAL OF FLUID MECHANICS
(2023)
Review
Engineering, Marine
Momchil Terziev, Tahsin Tezdogan, Atilla Incecik
Summary: This review article explores the problems with extrapolation procedures in naval architecture, the attempts to correct them and the current efforts to eliminate the need for extrapolation through full-scale Computational Fluid Dynamics. Despite progress, there are still bottlenecks in terms of data availability and computational power.
Article
Instruments & Instrumentation
Rui Liu, Heng Zhao, Liang Wang, Jiamei Jin, Yifeng Wu
Summary: This paper proposed a novel piezoelectric caudal fin thruster with an open and simple structure, utilizing the piezoelectric effect and direct friction drive principle. It is easy to miniaturize and is lighter, smaller, and more efficient than previously reported caudal fin thrusters based on ionic polymer-metal composites and shape memory alloys. Experimental results confirmed its effectiveness and scalability.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2022)
Article
Mechanics
Markus Scherer, Markus Uhlmann, Aman G. Kidanemariam, Michael Krayer
Summary: The study reveals the connection between the formation of subaqueous sediment ridges and the lateral organization of large-scale streaks, with ridges mostly appearing below large-scale low-speed streaks. The adaptation of sediment bedforms to changes in the outer flow with a time delay is described as a 'top-down' process. The presence of mean secondary currents of comparable intensity and spacing over sediment ridges and smooth-wall channels indicates the influence of regularly organized large-scale streaks.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Engineering, Marine
Haibo Liu, Yinxin Zhou, Xiaozhong Ren, Shengshui Liu, Hangfei Liu, Meng Li
Summary: Hydrodynamics is crucial in recirculating aquaculture systems (RAS). An efficient flow field is essential for creating a healthy environment for fish growth and development. This study proposes a fluid-solid coupled model based on computational fluid dynamics (CFD) to investigate the interaction between fish movement and the flow field. The results highlight the effectiveness of the numerical modeling method for studying fish movement and flow fields in RAS.
Article
Mechanics
Zisong Zhou, Chun-Xiao Xu, Javier Jimenez
Summary: The study found that the large-scale motions in the outer region of wall-bounded flows have a top-down influence on the spanwise motion of near-wall streaks. However, the density of streaks is weakly related to LSMs. Numerical experiments also showed that near-wall streaks merging is not strongly correlated with the generation of LSMs.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Environmental Sciences
R. Karthik, R. S. Robin, R. Purvaja, V Karthikeyan, B. Subbareddy, K. Balachandar, G. Hariharan, D. Ganguly, V. D. Samuel, T. P. S. Jinoj, R. Ramesh
Summary: This study investigated the abundance and distribution of microplastics in coastal areas of Palk Bay and Gulf of Mannar, and found that microplastics were present in both sediments and marine organisms, causing adverse health effects in fish. The study also discovered that microbial interactions contributed to the weathering of microplastics.
ENVIRONMENTAL POLLUTION
(2022)
Article
Environmental Sciences
Gorazd Novak, Jose M. Dominguez, Angelo Tafuni, Ana T. Silva, Polona Pengal, Matjaz Cetina, Dusan Zagar
Summary: Man-made barriers in fluvial systems are a major cause of declining migratory fish populations worldwide, with fish passages offering a solution to mitigate these issues. This study focuses on characterizing the flow pattern in a bottom ramp, using a 3-D numerical model based on the SPH method. The development of new tools during the study enhances the applicability of DualSPHysics in the field of eco-hydraulics.
Article
Mechanics
Xueguang Meng, Zengshuang Chen, Yang Zhang, Gang Chen
Summary: The phenomenon of cluster movements of fish, birds, and insects is universal in nature, and its aerodynamic performance is influenced by spatial arrangements. At a specific spacing, the overall thrust of the group can increase by about 40%, while the overall lift remains unchanged. The overall lift of the group decreases with an increase in the number of individuals, while the thrust remains unchanged. The downwash of the vortex wake plays a dominant role in the aerodynamic interference.
Article
Multidisciplinary Sciences
Richard Schweitzer, Martin Rolfs
Summary: The intrasaccadic retinal trace of an object, previously thought to be unavailable for visual processing, facilitates the establishment of object correspondence and initiates gaze correction during rapid eye movements.
Article
Chemistry, Multidisciplinary
Yuhan Li, Jialei Song, Ling Yin, Bowen Jin, Bo Yin, Yong Zhong
Summary: The hydrodynamics of a crucian carp during a C-type fast start were studied using a three-dimensional CFD model. The study confirmed that the jets induced by the fast start generate force, and the vortex rings generated in the preparation and propulsion stages are connected. An obvious vortex ring generated by the head during the propulsion stage was observed, which potentially benefits the rotational motion during the fast start. The study established a model to analyze the internal torque based on the hydrodynamic information, confirming the existence of neuromechanical phase lag during the fast start of fish. This study has potential benefits for the design of robot fish in terms of kinematics and driving mode.
APPLIED SCIENCES-BASEL
(2023)
Article
Mechanics
S. Panday, J. M. Floryan
Summary: It is shown that streaks and rolls can be created in a controlled manner in fully developed shear layers using spatially distributed heating, with their spatial distribution dictated by the heating pattern. The method is applicable for any Reynolds number and heating intensity. The energy costs of streak formation in laminar flows have been determined.
Article
Engineering, Marine
Gang Wang, Tobias Martin, Liuyi Huang, Hans Bihs
Summary: This study investigates the hydrodynamics and non-linear interaction between the submersible steel-frame offshore fish farm ShenLan 1 and regular waves using the open-source CFD toolbox REEF3D. The effects of wave parameters, net sheets, and structural variations on the motion responses and mooring forces are studied. The study provides indications towards a systemic evaluation of the dependencies of different structural parts of a submersible steel-frame offshore fish farm for hydrodynamics.
Article
Environmental Sciences
Sadia Sabrina, Quinn Lewis, Bruce Rhoads
Summary: Despite the recognition of complex hydrodynamic conditions at confluences, there have been few studies mapping spatial flow patterns and their variations over time. Using LSPIV technology, this study mapped the two-dimensional flow structure at a confluence and observed characteristics such as stagnation zones, low velocity areas, and mixing interfaces. Results also showed the fluctuation in interaction between incoming flows over time, possibly due to instability in the water-surface pressure-gradient field.
WATER RESOURCES RESEARCH
(2021)
Article
Environmental Sciences
Adam S. Candy, Shannara K. Taylor K. Parkins, Fleur C. Van Duyl, Benjamin Mueller, Milou G. I. Arts, Will Barnes, Marie Carstensen, Yun J. H. Scholten, Yusuf C. El-Khaled, Christian Wild, Linda Wegley Kelly, Craig E. Nelson, Stuart A. Sandin, Mark J. A. Vermeij, Forest L. Rohwer, Cristian Picioreanu, Paolo Stocchi, Andreas F. Haas
Summary: One mechanism that gives fleshy algae a competitive edge over corals during reef degradation is the occurrence of algal-induced and microbially-mediated hypoxia, which is typically less than 69.5 mu mol oxygen L-1. Algae are more tolerant of low oxygen conditions and may outcompete corals weakened by hypoxia. The extent of local hypoxic zones in highly turbulent aquatic environments, continuously flushed by currents and wave surge, remains a question unanswered.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Engineering, Mechanical
Mohamed Elshalakani, Christoph Bruecker
JOURNAL OF FLUIDS AND STRUCTURES
(2020)
Article
Chemistry, Analytical
Mohamed Elshalakani, Muthukumar Muthuramalingam, Christoph Bruecker
Article
Multidisciplinary Sciences
Muthukumar Muthuramalingam, Dominik K. Puckert, Ulrich Rist, Christoph Bruecker
SCIENTIFIC REPORTS
(2020)
Article
Engineering, Aerospace
Omar Selim, Erwin R. Gowree, Christian Lagemann, Edward Talboys, Chetan Jagadeesh, Christoph Brucker
Summary: The peregrine falcon was observed to adopt specific flight configurations during high-speed pullout, resulting in aerodynamic advantage due to lift-generating vortical structures over the wing. Wind-tunnel experiments and computational fluid dynamics simulations demonstrated the importance of hand wing deployment in creating extra vortex lift for increased stability and responsiveness.
Article
Acoustics
Edward Talboys, Thomas F. Geyer, Florian Pruefer, Christoph Bruecker
Summary: This study investigates the acoustic properties of a standard NACA 0012 airfoil with additional self-oscillating passive flaplets for self-noise reduction. Different flaplet configurations were observed to affect the oscillation and reduction of tonal noise.
Article
Engineering, Mechanical
Qianhui Li, Evangelos Stavropoulos-Vasilakis, Phoevos Koukouvinis, Manolis Gavaises, Christoph H. Bruecker
Summary: This study developed a method for calibrating wall-shear stress sensors in complex geometries, assisted by numerical simulation data. By calibrating and testing in the aorta model, it demonstrated the different impacts of two different heart valves on wall-shear stress in the aortic arch.
JOURNAL OF FLUIDS AND STRUCTURES
(2021)
Article
Thermodynamics
Zhihan Zhang, Qianhui Li, Christoph Bruecker, Qiang Zhang
Summary: This paper presents a combined experimental and numerical study on high-amplitude intermittent impingement cooling. The results show a remarkable improvement in overall cooling efficiency, especially in the wall jet region.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Multidisciplinary Sciences
Raphael Glick, Muthukumar Muthuramalingam, Christoph Brucker
Summary: Previous research has shown that sea lions are able to detect the direction of oncoming vortices using their whiskers. In this study, a theoretical model based on multilateration is presented and tested through experimental studies. The results demonstrate that arrays of whiskers can function as antennas to determine the direction of arrival.
SCIENTIFIC REPORTS
(2022)
Article
Thermodynamics
Alecsandra Court, Omar Selim, Keith Pamment, Christoph Bruecker
Summary: This paper investigates the flow control mechanism induced by the dynamic motion cycles of bio-inspired flaplets on a model wing. The experiment results show that the opening of flaplets induces backflow underneath, while the closure generates a forward directed jet, which re-energizes the boundary layer flow upstream. This study provides insights into the action of pop-up feathers for separation control and gust control.
INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW
(2023)
Article
Physics, Fluids & Plasmas
Omar Selim, Christoph Brucker
Summary: This paper introduces a novel approach to sense and characterize flow over an aerofoil using arrays of flexible wind-hair-like sensors. The sensors provide real-time readings of local flow information with high temporal resolution, and were tested in a wind tunnel with varying angles of attack. The sensors were able to detect low-frequency oscillations, potentially linked to the breathing modes of the laminar separation bubble.
Review
Energy & Fuels
Elisa Colas, Elena-Maria Klopries, Deyan Tian, Maike Kroll, Michael Selzner, Christoph Bruecker, Kavan Khaledi, Peter Kukla, Axel Preusse, Carolina Sabarny, Holger Schuettrumpf, Florian Amann
Summary: This paper explores the potential of using abandoned mines as lower reservoirs for Underground Pumped Storage Power Systems (UPSPs) and addresses the challenges associated with repurposing coal mines. Numerical solutions to mitigate cyclical processes in abandoned mines are presented, and the economic feasibility of repurposing mines is assessed.
JOURNAL OF ENERGY STORAGE
(2023)
Article
Physics, Fluids & Plasmas
Raphael Glick, Muthukumar Muthuramalingam, Christoph Brucker
Summary: The study demonstrates that coherent vortical structures can be detected by analyzing the bending deformations of whiskers, even in noisy environments. This has important implications for developing sensory systems that can overcome high noise levels.
Article
Engineering, Multidisciplinary
Muthukumar Muthuramalingam, Edward Talboys, Hermann Wagner, Christoph Bruecker
Summary: This study presents a novel mechanism for laminar flow control on straight and backward swept wings, inspired by owl feathers. By designing a comb-like device based on owl feather barbs and conducting experiments and numerical studies, the researchers found that this device creates a flow turning effect in the boundary layer to counteract cross-flow, ultimately delaying transition. The observed effect is expected to contribute to a more silent flight in owl flight.
BIOINSPIRATION & BIOMIMETICS
(2021)