Bulletin of the American Physical Society
66th Annual Meeting of the APS Division of Fluid Dynamics
Volume 58, Number 18
Sunday–Tuesday, November 24–26, 2013; Pittsburgh, Pennsylvania
Session M22: General Fluid Dynamics III |
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Chair: Shahram Pouya, Michigan State University Room: 317 |
Tuesday, November 26, 2013 8:00AM - 8:13AM |
M22.00001: Flow interaction between multiple cross-flow inlets in a horizontal pipe or channel Pranab N. Jha, Chuck Smith, Ralph W. Metcalfe Incompressible flow in horizontal channels and pipes with multiple cross-flow inlets was studied numerically. Flow interference among the inlets was studied using an axisymmetric pipe flow model with five cross-flow inlets. Three basic flow regimes - trickle flow, partially blocked flow and fully blocked flow - were identified with respect to the blocking of upstream inlets by the downstream ones. The effects of inlet pressure and inlet size on the flow regimes under steady state conditions were studied. The presence of these regimes was supported by field data obtained from a horizontal natural gas well at two different times in the production cycle. Using a hydrostatic pressure model of reservoirs as the inlet boundary condition that drained fluid into the channel, the dynamic interaction of the inlets was studied. The transient behavior of the flow regimes was simulated and the key time-scales involved were identified. This is supported by field data where a similar behavior can be observed over time. Initially, the upstream inlets were in a blocked state, but opened up at a later time, leading to a trickle flow regime. [Preview Abstract] |
Tuesday, November 26, 2013 8:13AM - 8:26AM |
M22.00002: Direct numerical simulation of electrokinetic chaos driven by ion concentration polarization next to an ion-selective membrane Clara Druzgalski, Mathias Andersen, Ali Mani We present a three-dimensional direct numerical simulation (DNS) of electrokinetic instability and hydrodynamic chaos near an ion-selective membrane subject to normal electric current. We employ a non-dissipative computational algorithm to numerically solve the full Poisson-Nernst-Planck and Navier-Stokes equations for a symmetric binary electrolyte in a gap between an ion-selective surface and a stationary reservoir. In our simulation the numerically stiff electric double layer (EDL) and extended space charge (ESC) regions are resolved without resorting to asymptotic models. Our 3D results enable visualization of the onset of instability and detailed flow structures over a wide range of scales and distances to the membrane. We present the time-averaged statistics from this simulation and its comparison to an otherwise identical 2D calculation. These simulations demonstrate transport phenomena that are crucial for accurate prediction of charge and mass transport in various electrochemical systems such as flow batteries and electrodialysis and electrolysis cells. [Preview Abstract] |
Tuesday, November 26, 2013 8:26AM - 8:39AM |
M22.00003: Mixing Dynamics Between Water and Biofuels Aline Cotel, Avery Demond, Jiariu Lei, Erica Green Currently, ethanol-based biofuels are considered to be among the best alternatives to gasoline. However, the potential environmental impact of a spill of such fuels on aquatic environments is an area of open discussion and research. Since these fuels are a combination of a miscible fluid (ethanol) and an immiscible fluid (gasoline), models used for traditional gasoline fuels (immiscible in water) are not applicable. Preliminary experiments show that when a solution of ethanol and glycol is mixed with water, a third mixed fluid is formed. Two distinct mixing regimes are observed. A turbulent wake is created between the ethanol/glycol and water layers to cause the ethanol and glycol solution to entrain and mix into with the water phase. In the first regime, due to nonlinear mixing behavior, a dramatic overturning is possible for a certain range of parameters. The second regime begins when the turbulent wake has dissipated and the internal wave created by the plate has begun to settle, typically within the first minute. At this point, B\'{e}nard-like cells, similar to those typically seen in Rayleigh-B\'{e}nard convection, form at the interface and relatively slow mass transfer is evident. Both regimes are described quantitatively with a set of dimensionless parameters. [Preview Abstract] |
Tuesday, November 26, 2013 8:39AM - 8:52AM |
M22.00004: Measurement of Submerged Oil/Gas Leaks using ROV Video Franklin Shaffer, Giorgio de Vera, Kenneth Lee, \"Omer Savas Drilling for oil or gas in the Gulf of Mexico is increasing rapidly at depths up to three miles. The National Commission on the Deepwater Horizon Oil Leak concluded that inaccurate estimates of the leak rate from the Deepwater Horizon caused an inadequate response and attempts to cap the leak to fail. The first response to a submerged oil/gas leak will be to send a Remotely Operated Vehicle (ROV) down to view the leak. During the response to the Deepwater Horizon crisis, the authors Savas and Shaffer were members of the Flow Rate Technical Group's Plume Team who used ROV video to develop the FRTG's first official estimates of the oil leak rate. Savas and Shaffer developed an approach using the larger, faster jet features (e.g., turbulent eddies, vortices, entrained particles) in the near-field developing zone to measure discharge rates. The authors have since used the Berkeley Tow Tank to test this approach on submerged dye-colored water jets and compressed air jets. Image Correlation Velocimetry has been applied to measure the velocity of visible features. Results from tests in the Berkeley Tow Tank and submerged oil jets in the OHMSETT facility will be presented. [Preview Abstract] |
Tuesday, November 26, 2013 8:52AM - 9:05AM |
M22.00005: ABSTRACT WITHDRAWN |
Tuesday, November 26, 2013 9:05AM - 9:18AM |
M22.00006: Aerodynamic damping of oscillating cantilevers from side walls in close proximity Andrew Eastman, Mark Kimber As a result of their simplicity, low power consumption, and relative ease of implementation, oscillating cantilevers have been investigated for use in many applications. However, use in many circumstances requires a close proximity to one or multiple boundaries. This can cause added damping to the flow that inhibits the operational effectiveness. This paper investigates the fluidic damping effect of two boundaries parallel to the oscillating motion of the fan at multiple voltage and frequency inputs. Experiments performed across a range of operating conditions showed that decreasing the distance between the boundaries and the oscillating cantilever increases the aerodynamic damping, which can be as high as 5X compared to normal (i.e., without sidewalls) operation. However this also decreases the power consumption which can be beneficial under certain circumstances. The power consumption also peaks when operating at resonance. The findings in the paper are significant to creating a basis to judge how to best operate an oscillating cantilever to achieve the maximum operational effectiveness. [Preview Abstract] |
Tuesday, November 26, 2013 9:18AM - 9:31AM |
M22.00007: Growth and Decay of Fully-Developed Dean Flow Jesse Ault, John Davis Flows in curved pipes are ubiquitous in piping systems, hydraulics, and even biological systems. Beginning with the pioneering work of Dean in the 1920s, there have been many studies of the development of flow in curved pipes. However, the opposite problem has been little studied: the decay of fully-developed flow in a curved pipe after exiting into a straight outlet.~First, we study the entry length of flow in a curved pipe and compare our results with previously published work. Then, we study the problem of decay and provide a description of the transition of the fully-developed curved-pipe flow to the fully developed flow in a straight pipe. In particular,~OpenFOAM's icoFOAM solver is used to perform direct numerical simulations in the geometry of curved pipes of varying curvature connected with straight outlets. The magnitude of vorticity, wall shear stress, and centerline velocity are plotted along the pipe while varying the Reynolds number and the ratio of the pipe radius to the radius of curvature. The development and decay lengths of the curved-pipe flow are then related to these two parameters.~A simple model for the observed dynamics will be presented. [Preview Abstract] |
Tuesday, November 26, 2013 9:31AM - 9:44AM |
M22.00008: An analytical approach to fluid ratcheting in oscillatory boundary layer Jie Yu It is well known that oscillatory flows close to a rigid or flexible boundary induces a steady streaming due to viscosity. Under progressive motions, this becomes a unidirectional streaming near the boundary (e.g. mass transport or peristaltic pumping in water waves). This mechanism is shared by the phenomenon of ratcheting fluid in a narrow channel by vibrating the channel walls that are lined with asymmetric corrugations (shown by a recent experiment BAPS.2010.DFD.HC.3). A theory is presented here to describe the ratcheting effects in such a channel. A conformal transformation method, developed for waves over arbitrary periodic topographies (Yu \& Howard, {\em J. Fluid Mech.} 2012), is adapted to deal with large corrugations of the channel walls. Under the assumption that the wall oscillations are of small amplitude, the vorticity dynamics can be analyzed in the mapped plane, obtaining the solution that describes the steady streaming field due to nonlinear convective inertia. The results are discussed, regarding the dependency of the pumping direction on the oscillation frequency of the walls and the effects of the end position relative to the phase of corrugations in the case of a finite length channel. Preliminary experimental data will be presented if time permits. [Preview Abstract] |
Tuesday, November 26, 2013 9:44AM - 9:57AM |
M22.00009: Multiple shock-induced luminescence in water Pedro Quinto-Su Luminescence in microscopic volumes of water is observed as a result of the superposition of several laser-induced shocks created by optical breakdown. [Preview Abstract] |
Tuesday, November 26, 2013 9:57AM - 10:10AM |
M22.00010: ABSTRACT WITHDRAWN |
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