Article
Thermodynamics
Adriano Sueke Takata, Josuel Kruppa Rogenski, Leandro Franco de Souza
Summary: The translation mainly involves the influence of Gortler vortices on boundary layer flows and the competition relationship between nonlinear modes. The results show that the amplification rate of high-frequency excited modes is lower, and when high-frequency three-dimensional waves are introduced, the transition process is dominated by the super-harmonic mode.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Mechanics
Ganglei Huang, Wufei Si, Cunbiao Lee
Summary: This study visualizes naturally developing Gortler streaks using Rayleigh scattering technique for the first time in hypersonic flow, showing that three-dimensional waves play a crucial role in the formation of Gortler streaks and mushroom-like structures.
Article
Mechanics
Xian-Dong Li, Yong-Liang Yu, Lin Bao
Summary: This paper investigates the separation angle and peak pressure of hypersonic compression corner flows with separated regions at low-to-medium Reynolds number, introducing an equivalent double shocks inviscid flow model for peak pressure. The results show that the separation angle is almost independent of the freestream Mach number, and the ratio of peak pressure to freestream pressure is approximately proportional to the square of the freestream Mach number under strong viscous interaction conditions.
Article
Mechanics
Ken Chun Kit Uy, Jiaao Hao, Chih-Yung Wen
Summary: This study investigates the coexistence of stationary Gortler and crossflow instabilities in boundary layers covering incompressible to hypersonic regimes through linear stability analysis. The results show that varying the local sweep angle, pressure gradient, wall curvature, and wall temperature affects the instability. Synchronization between the two modes, referred to as Gortler-crossflow modes, is identified under certain conditions.
Article
Thermodynamics
Karthikeyan Jagadeesan, Vagesh D. Narasimhamurthy, Helge I. Andersson
Summary: This study revisits the direct numerical simulation (DNS) of rib-roughened turbulent channel flow rotating about its spanwise axis. The combined effects of roughness and Coriolis force on turbulence were analyzed. The results showed that rotation caused preferential aligning of near-wall vortical structures and the rotational production rates played a significant role in distributing kinetic energy. The structure of turbulence was significantly affected by rotation.
INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW
(2022)
Article
Multidisciplinary Sciences
Manjul Sharma, K. Aswathy Nair, R. Vishnu, A. Sameen
Summary: Taylor-Couette flow is used to study Taylor-Gortler (TG) instability and associated vortices. Computational study confirms the presence of TG-like near-wall vortical structures in Vogel-Escudier (VE) and lid-driven cavity (LDC) flows. These vortices are observed in chaotic regimes in both flows, with VE flow transitioning from a steady state and LDC flow exhibiting a limit cycle.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2023)
Article
Engineering, Aerospace
Muqing Yang, Dongli Ma, Liang Zhang
Summary: The temperature difference between the solar cells on the upper surface of a solar unmanned aerial vehicle (UAV) wing and the atmospheric temperature during flight can induce buoyancy-driven Gortler vortices, which affect the aerodynamic characteristics of the wing. In this study, a hybrid RANS-LES-based approach was used to simulate the flow above a heated flat plate and analyze the influence of Gortler vortices under different flow velocities and temperature differences. The results showed that the presence of buoyancy-driven Gortler vortices increased the friction drag coefficient and the intensity of the vortices increased with higher temperature differences and lower flow velocities.
Article
Physics, Multidisciplinary
Aaron Hui, Brian Skinner
Summary: A resistor at finite temperature produces white noise fluctuations of the current called Johnson-Nyquist noise, which can be used to measure the electron temperature. While the Johnson-Nyquist theorem has been generalized for Ohmic devices, a similar generalization is needed for hydrodynamic electron systems. In a rectangular geometry, low-frequency Johnson noise in the hydrodynamic setting is found to be geometry dependent due to nonlocal viscous gradients, but ignoring the geometric correction only leads to a maximum error of 40% compared to the Ohmic result.
PHYSICAL REVIEW LETTERS
(2023)
Article
Mechanics
Bingbing Wan, Guohua Tu, Xianxu Yuan, Jianqiang Chen, Yifeng Zhang
Summary: This study confirms the presence of traveling crossflow waves under real flight conditions by analyzing raw data from a model flight experiment, with the signals detected being in good agreement with predictions based on linear stability theory.
Article
Physics, Multidisciplinary
Xiumei Qiao, Ke Lan
Summary: The study introduces a novel HDC-CH capsule design that significantly reduces the ablation front growth factor, thus enhancing the potential for successful ICF ignition.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Yonatan Messica, Pavel M. Ostrovsky, Dmitri B. Gutman
Summary: We investigate heat transport in a Weyl semimetal with broken time-reversal symmetry in the hydrodynamic regime. The longitudinal heat conductivity is determined by momentum relaxation time, while the longitudinal electric conductivity is controlled by inelastic scattering time. The presence of the Seebeck effect affects the heat conductivity and Lorenz ratio, with the transverse heat conductivity being enhanced by the transverse Seebeck effect.
Article
Environmental Sciences
Ilja Maljutenko, Ida-Maja Hassello, Martin Eriksson, Erik Ytreberg, Daniel Yngsell, Lasse Johansson, Jukka-Pekka Jalkanen, Mariliis Kouts, Mari-Liis Kasemets, Jana Moldanova, Kerstin Magnusson, Urmas Raudsepp
Summary: Major sources of pollution from shipping to marine environments include antifouling paint residues and various types of water discharges. Studies have shown that the dispersion of contaminants is influenced by surface kinetic energy and vertical stratification at the discharge location, with an elevated concentration persisting for about two days and dispersing over a spatial scale of 10-60 km.
MARINE POLLUTION BULLETIN
(2021)
Article
Nanoscience & Nanotechnology
Suhail Abbas, Abdullah Shah, Zahid Hussain, Shahid Hussain
Summary: The study compares the performance of three linear solvers for numerically solving the three-dimensional incompressible Navier-Stokes equations, showing that the LGS solver is more reliable than PGS and ADI solvers.
Article
Environmental Sciences
Ove Parn, Diego Macias Moy, Adolf Stips
Summary: This study used a hydrodynamic model and a particle-tracking model to investigate the transport patterns and accumulation areas of marine litter in the Baltic Sea. It also examined the extent of marine litter from major polluting rivers. Mapping of marine plastic debris distribution in 2017-2018 revealed that the largest accumulation area is between latitude 59 degrees N and 61 degrees N, encompassing the Northern Baltic Proper, Archipelago Sea, and the Gulf of Finland. Floating plastic spreads from the major pollution sites, River Vistula, Oder, and Neman, to the waters of all countries surrounding the Baltic Sea.
MARINE POLLUTION BULLETIN
(2023)
Article
Engineering, Marine
Georgios Klonaris, Frans Van Eeden, Jeffrey Verbeurgt, Peter Troch, Denis Constales, Hans Poppe, Alain De Wulf
Summary: The study focuses on developing and validating a state-of-the-art three-dimensional numerical model as the basis for a compound operational and forecasting tool for the Belgian coastal zone. The model’s behavior throughout the North Sea and its response to meteorological conditions have been validated, showing good agreement with observations.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2021)
Article
Geochemistry & Geophysics
Hamid Varikkodan, S. Balaji, S. Arjun
Summary: This study evaluated the surge heights and wave characteristics of a cyclone storm event in the Andaman Islands in November 2013. The results showed higher surges on the east coast and stronger waves on the right side of the cyclone.
DYNAMICS OF ATMOSPHERES AND OCEANS
(2024)