Improvement of acoustic theory of ultrasonic waves in dilute bubbly liquids (2009)
Ando, Keita, Colonius, Tim, Brennen, Christopher E.
The theory of the acoustics of dilute bubbly liquids is reviewed, and the dispersion relation is modified by including the effect of liquid compressibility on the natural frequency of the bubbles....
Numerical simulations of non-spherical bubble collapse (2009)
A high-order accurate shock- and interface-capturing scheme is used to simulate the collapse of a gas bubble in water. In order to better understand the damage caused by collapsing bubbles, the...
We continue the development of the super-grid-scale model initiated in [T. Colonius, H. Ran, A super-grid-scale model for simulating compressible flow on unbounded domains, J. Comput. Phys. 182 (1)...
Three-dimensional flows around low-aspect-ratio flat-plate wings at low Reynolds numbers (2009)
Kunihiko, Taira, Colonius, Tim
Three-dimensional flows over impulsively translated low-aspect-ratio flat plates are investigated for Reynolds numbers of 300 and 500, with a focus on the unsteady vortex dynamics at post-stall...
Effect of Tip Vortices in Low-Reynolds-Number Poststall Flow Control (2009)
Taira, Kunihiko, Colonius, Tim
We numerically investigate the application of steady blowing to three-dimensional stalled flows around low-aspect-ratio rectangular flat-plate wings at a Reynolds number of 300. The objective of this...
Shock-induced collapse of a gas bubble in shockwave lithotripsy (2008)
The shock-induced collapse of a pre-existing nucleus near a solid surface in the focal region of a lithotripter is investigated. The entire flow field of the collapse of a single gas bubble subjected...
Physical & Computational Modeling of Heat Transfer for Titan Montgolfiere Balloons (2008)
Appeloe, Daniel, Nott, Julian, Colonius, Tim
This presentation was part of the session : Probe Missions to the Giant Planets, Titan and Venus
Statistical equilibrium of bubble oscillations in dilute bubbly flows (2008)
Colonius, Tim, Hagmeijer, Rob, Ando, Keita, Brennen, Christopher E.
The problem of predicting the moments of the distribution of bubble radius in bubbly flows is considered. The particular case where bubble oscillations occur due to a rapid (impulsive or step change)...
Three-dimensional instabilities in compressible flow over open cavities (2008)
Brès, Guillaume A., Colonius, Tim
Direct numerical simulations are performed to investigate the three-dimensional stability of compressible flow over open cavities. A linear stability analysis is conducted to search for...
Greater Seattle, Washington NUMERICAL INVESTIGATION OF THE FLOW PAST A CAVITY (2007)
Numerical simulations are used to investigate the resonant instabilities in the ow past an open cavity. The compressible Navier-Stokes equations are solved directly (no turbulence model) for...
Clarence W. Rowley, Tim Colonius
Many compressible ow and aeroacoustic computations rely on accurate nonre ecting or radiation boundary conditions. When the equations and boundary conditions are discretized using a nite-di erence...
AIAA 2001-2126 DYNAMICAL MODELS FOR CONTROL OF CAVITY OSCILLATIONS (2007)
Clarence W. Rowley, Tim Colonius, Richard M. Murray
We investigate nonlinear dynamical models for selfsustained oscillations in the flow past a rectangular cavity. The models are based on the method of Proper Orthogonal Decomposition (POD) and...
Instability waves in a subsonic round jet detected using a near-field phased microphone array (2006)
We propose a diagnostic technique to detect instability waves in a subsonic round jet using a phased microphone array. The detection algorithm is analogous to the beam-forming technique, which is...
Linear models for control of cavity flow oscillations (2006)
Rowley, Clarence W., Williams, David R., Colonius, Tim, Murray, Richard M., MacMynowski, Douglas G.
Models for understanding and controlling oscillations in the flow past a rectangular cavity are developed. These models may be used to guide control designs, to understand performance limits of...
Suzuki, Takao, Colonius, Tim, Pirozzoli, Sergio
We develop a reduced-order model for large-scale unsteadiness (vortex shedding) in a two-dimensional diffuser and use the model to show how periodic mass injection near the separation point reduces...
Modeling Artificial Boundary Conditions for Compressible Flow (2004)
We review artificial boundary conditions (BCs) for simulation of inflow, outflow, and far-field (radiation) problems, with an emphasis on techniques suitable for compressible turbulent shear flows....
A dilating vortex particle method for compressible flow (2002)
Eldredge, Jeff D., Colonius, Tim, Leonard, Anthony
Vortex methods have become useful tools for the computation of incompressible fluid flow. In this work, a vortex particle method for the simulation of unsteady two-dimensional compressible flow is...
On self-sustained oscillations in two-dimensional compressible flow over rectangular cavities (2002)
Rowley, Clarence W., Colonius, Tim, Basu, Amit J.
Numerical simulations are used to investigate the resonant instabilities in two-dimensional flow past an open cavity. The compressible Navier–Stokes equations are solved directly (no turbulence...
Preston, Al, Colonius, Tim, Brennen, Christopher E.
The Rayleigh-Plesset equation is used extensively to model spherical bubble dynamics, yet is has been shown that it cannot correctly capture damping effects due to mass and thermal diffusion. Full...
Preston, Al T., Colonius, Tim, Brennen, Christopher E.
The Rayleigh-Plesset equation is used extensively to model spherical bubble dynamics, yet it has been shown that it cannot correctly capture damping effects due to mass and thermal diffusion. Full...
Numerical Simulation of Bubbly Cavitating Flow in Shock Wave Lithotripsy (2001)
Tanguay, Michel, Colonius, Tim
The bubbly cavitating .ow generated by a lithotriptor is computed using an ensemble averaged two-phase .ow model. The time-dependent, compressible .ow computation is divided into two separate...
Numerical experiments on vortex ring formation (2001)
Mohseni, Kamran, Ran, Hongyu, Colonius, Tim
Numerical simulations are used to study the formation of vortex rings that are generated by applying a non-conservative force of long duration, simulating experimental vortex ring generation with...
Numerical experiments on vortex ring formation (2001)
Kamran Mohseni, Hongyu Ran, Tim Colonius
Numerical simulations are used to study the formation of vortex rings that are generated by applying a non-conservative force of long duration, simulating experimental vortex ring generation with...
A Numerical Investigation of Unsteady Bubbly Cavitating Nozzle Flows (2000)
Preston, Al, Colonius, Tim, Brennen, Christopher E.
The effects of unsteady bubble dynamics on cavitating flow through a converging-diverging nozzle are investigated numerically. A continuum model that couples the Rayleigh-Plesset equation with the...
NOTE Numerical Treatment of Polar Coordinate Singularities (1999)
The treatment of the geometrical singularity in cylindrical and spherical coordinates has for many years been a difficulty in the development of accurate finite difference (FD) and pseudo-spectral...
Direct Numerical Simulation of Aerodynamic Noise. (1998)
Moin, Parviz, Lele, Sanjiva K., Colonius, Tim
Direct Numerical Simulation of Aerodynamic Noise is a part of an overall research program in compressible turbulence including the study of the physics of compressible turbulence, shock-turbulence...
A Unified View of Global Instabilities of Compressible Flow Over Open Cavities (1998)
Colonius, Tim, Bres, Guillaume
We report progress in our ongoing effort to compute and understand the three-dimensional instabilities (resonance) of open cavity flows from incompressible to supersonic speeds. In particular, our...
Computation of Shock Waves in Cavitating Flows (1998)
Colonius, Tim, Brennen, Christopher E., D'Auria, Fabrizio
Realistic cavitating flows are dominated by a large number of interacting bubbles. These clouds of bubbles exhibit highly nonlinear behavior with sudden changes in void fraction. Because of the...
Computing Shock Waves in Cloud Cavitation (1998)
Brennen, Christopher E., Colonius, Tim, D'Auria, Fabrizio
This paper presents a numerical investigation of some of the phenomena involved in the nonlinear dynamics of a homogeneous bubbly mixture bounded by an oscillatory wall. This problem represents an...
Sound generation in a mixing layer (1997)
Colonius, Tim, Lele, Sanjiva K., Moin, Parviz
The sound generated by vortex pairing in a two-dimensional compressible mixing layer is investigated. Direct numerical simulations (DNS) of the Navier-Stokes equations are used to compute both the...
Direct computation of aerodynamic sound / (1994)
Thesis (Ph. D.)--Stanford University, 1994.
Statistical equilibrium of bubble oscillations in dilute bubbly flows
Colonius, Tim, Hagmeijer, Rob, Ando, Keita, Brennen, Christopher E.
The problem of predicting the moments of the distribution of bubble radius in bubbly flows is considered. The particular case where bubble oscillations occur due to a rapid (impulsive or step change)...
Improvement of acoustic theory of ultrasonic waves in dilute bubbly liquids
Ando, Keita, Colonius, Tim, Brennen, Christopher E.
The theory of the acoustics of dilute bubbly liquids is reviewed, and the dispersion relation is modified by including the effect of liquid compressibility on the natural frequency of the bubbles....
Shock-induced collapse of a gas bubble in shockwave lithotripsy
The shock-induced collapse of a pre-existing nucleus near a solid surface in the focal region of a lithotripter is investigated. The entire flow field of the collapse of a single gas bubble subjected...