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We study the generation, nonlinear development and secondary instability of unsteady G\"ortler vortices and streaks in compressible boundary layers exposed to free-stream vortical disturbances and evolving over concave, flat and convex…

Fluid Dynamics · Physics 2024-12-11 Dongdong Xu , Pierre Ricco , Elena Marensi

Here, we investigate the linear spatial stability of a parallel two-dimensional compressible boundary layer on an adiabatic plate by considering 2D and 3D disturbances. We employ the Compound Matrix Method for the first time for…

Fluid Dynamics · Physics 2024-01-31 Neha Chaturvedi , Swagata Bhaumik , Rituparn Somvanshi

The paper considers a two-dimensional flow in a channel, which consists of straight inlet and outlet branches and a circularly 90-degree curved bend. An incompressible viscous fluid flows through the elbow under the action of a constant…

Fluid Dynamics · Physics 2022-04-06 Alexander Proskurin

The three-dimensional temporal instability of rotating boundary layer flows is investigated by computing classical normal modes as well as by evaluating the transient growth of optimal disturbances. The flows examined are the rotating…

Fluid Dynamics · Physics 2009-11-10 Philip Yecko , Maurice Rossi

Internal waves, or waves that propagate within a stratified fluid, may break and cause mixing. While each individual mixing event may be small, collectively, internal wave breaking drive processes in the ocean that are critical to…

The wake flow around a circular cylinder at $Re\approx100$ performing rotatory oscillations has been thoroughly discussed in the literature, mostly focusing on the modifications to the natural B\'enard-von K\'arm\'an vortex street that…

Fluid Dynamics · Physics 2015-05-18 Juan D'Adamo , Ramiro Godoy-Diana , José Eduardo Wesfreid

The presence of a no-slip, impermeable, adiabatic, sloped boundary in an otherwise quiescent, stably stratified, Boussinesq flow generates baroclinic vorticity within a diffusive boundary layer. Such conditions are typical of the…

Fluid Dynamics · Physics 2022-10-26 Bryan Kaiser , Lawrence Pratt

Disk accretion onto weakly magnetized astrophysical objects often proceeds via a boundary layer that forms near the object's surface, in which the rotation speed of the accreted gas changes rapidly. Here we study the initial stages of…

Solar and Stellar Astrophysics · Physics 2015-06-03 Mikhail Belyaev , Roman Rafikov

We investigate the linear instability of two-layer stratified shear flows in a sloping two-dimensional channel, subject to non-zero longitudinal gravitational forces. We reveal three previously unknown instabilities, distinct from the…

Fluid Dynamics · Physics 2023-09-20 Lu Zhu , Amir Atoufi , Adrien Lefauve , Rich R. Kerswell , P. F. Linden

We perform a three-dimensional, short-wavelength stability analysis on the numerically simulated two-dimensional flow past a circular cylinder for Reynolds numbers in the range $50\le Re\le300$; here, $Re = U_{\infty}D/\nu$ with $U_\infty$,…

Fluid Dynamics · Physics 2018-11-07 Yogesh Jethani , Kamal Kumar , A. Sameen , Manikandan Mathur

One of the main statistical features of near-neutral atmospheric boundary layer (ABL) turbulence is the positive vertical velocity skewness $Sk_w$ above the roughness sublayer or the buffer region in smooth-walls. The $Sk_w$ variations are…

Atmospheric and Oceanic Physics · Physics 2024-08-23 Elia Buono , Gabriel Katul , Michael Heisel , Davide Poggi , Cosimo Peruzzi , Davide Vettori , Costantino Manes

We derive and analyze well-posed, energy- and entropy-stable boundary conditions (BCs) for the two-dimensional linear and nonlinear rotating shallow water equations (RSWE) in vector invariant form. The focus of the study is on subcritical…

Numerical Analysis · Mathematics 2026-01-07 Kenneth Duru , Chuqiao Xu

Boundary-layer instabilities for a finned cone at Mach=6, $Re=8.4 \times 10^6$ [m$^{-1}$], and zero incidence angle are examined using linear stability methods of varying fidelity and maturity, following earlier analysis presented in…

Simultaneous two-phase particle image/tracking velocimetry (PIV/PTV) measurement is conducted on particle-laden turbulent boundary layer (TBL) over a horizontal smooth-flat-plate. The relatively high Reynolds number (Re{\tau}=5500 based on…

Fluid Dynamics · Physics 2018-11-19 Hang-Yu Zhu , Chong Pan , Jin-Jun Wang , Yi-Rui Liang

The wake of wavy cylinder has been shown to exhibit bistability. Depending on the initial condition, the final state of the wake can either develop into a steady flow (state I), or periodic shedding (state II). In this paper, we perform…

Fluid Dynamics · Physics 2022-09-01 Kai Zhang , Hongbo Zhu , Yong Cao , Dai Zhou

Laminar-to-turbulence transition in zero-pressure-gradient boundary layer at Mach 4.5 is studied using direct numerical simulations. For a given level of total disturbance energy, the inflow spectra was designed to correspond to the…

Fluid Dynamics · Physics 2018-12-03 Reza Jahanbakhshi , Tamer A. Zaki

This paper describes an experimental investigation, by means of hot-wire anemometry, of the characteristics of velocity and temperature in a rotating turbulent boundary layer under isothermal and non-isothermal conditions. The ranges of…

Fluid Dynamics · Physics 2022-08-24 Zhi Tao , Ruquan You , Yao Ma , Haiwang Li

In this paper we investigate a new instability of the Lamb-Chaplygin dipole in a stratified fluid. Through numerical linear stability analysis, a secondary peak in the growth rate emerges at vertical scales about an order of magnitude…

Fluid Dynamics · Physics 2018-04-25 Luke Bovard , Michael L. Waite

Time-dependent visualisations of large-scale direct and large-eddy simulations (DNS and LES) of a turbulent boundary layer reaching up to $Re_\theta=4300$ are presented. The focus of the present fluid dynamics video is on analysing the…

Fluid Dynamics · Physics 2010-10-20 Philipp Schlatter , Mattias Chevalier , Miloš Ilak , Dan S. Henningson

We study the transition to turbulence in the asymptotic suction boundary layer (ASBL) by direct numerical simulation. Tracking the motion of trajectories intermediate between laminar and turbulent states we can identify the invariant object…