In 2010 Bryden, Ingram and Wallace applied to the UK Engineering and Physical Sciences Research Council (EPSRC) for funding to construct the all waters combined current and wave test facility. Funding was awarded and over the next three years the FloWave TT facility was constructed. At its heart is a 25m diameter, circular basin, equipped with 168 force feedback wave makers, 28 bidirectional impellers and a liftable floor. The 2m deep test section is designed to generate currents (at 0.8m/s) and 700mm high, 2s period, waves from any relative directions. Allowing a model to be subjected to scale tests over the full tidal ellipse simultaneously with multi-directional waves.Construction of the facility was completed in November 2013, and calibration is currently in progress. Initial work has shown that maximum flows of 2ms −1 can be achieved across the test section, while the circular wave maker array allows very large focused waves to be created. This paper describes the FloWave facility, its construction and commissioning and presents some preliminary results.
Within an aero-engine, bearing chamber oil is provided for components to lubricate and cool. This oil must be efficiently removed (scavenged) from the chamber to ensure that it does not overheat and degrade. Bearing chambers typically contain a sump section with an exit pipe leading to a scavenge pump. In this paper, a simplified physical situation related to bearing chamber scavenge is computationally modeled. The volume of fluid (VOF) model of Hirt and Nichols (1981, “Volume of Fluid (VOF) Method for the Dynamics of Free Boundaries,” J. Comput. Phys., 39, pp. 201–225), implemented within the commercial computational fluid dynamics (CFD) code FLUENT (Fluent, 2006, Fluent 6.3 User’s Guide, 10 Cavendish Court, Lebanon, NH 03766), has been applied to investigate the case of transient draining in an axisymmetric vessel. The model is setup to match the experimental work of Lubin and Springer (1967, “The Formation of a Dip on the Surface of a Liquid Draining From a Tank,” J. Fluid Mech., 29(2), pp. 385–390). First, a comparison of the computational predictions with the experimental results for free draining is presented. Second, a comparison between the free surface positions obtained the developed VOF methodology and the results obtained by Zhou and Graebel (1990, “Axisymmetric Draining of a Cylindrical Tank With a Free Surface,” J. Fluid Mech., 221, pp. 511–532) using a boundary integral method is reported. When comparing the results with the observations of Lubin and Springer some differences are noted. These differences, which relate to the effect of initial height and outflow history, may have arisen due to the experimental procedure used by Lubin and Springer. This paper shows that CFD is a promising approach to analyzing these simple draining situations in terms of predicting bulk quantities, transitions, and free-surface shape and position.
CO2 flooding of a strong waterdrive reservoir has begun along the Texas Gulf Coast. Ninety (90) million SCF of CO2 will be injected daily during 2011 to re-pressure the reservoir and rates as high as 1 billion SCF per day (including recycle) will ultimately be used to develop this giant oil field. Design of this CO2 flood at a depth of 6,000 feet has focused upon pattern design, operating pressure, and the impact of aquifer influence. Success of CO2 floods, hinges upon the ability to increase reservoir pressure to, or near, miscibility pressure and to effectively sweep the reservoir. Laboratory and field performance data have been utilized to improve the design of this continuous CO2 injection project. Some of the largest oil reservoirs in the world are composed of high permeability sandstones with large aquifers. These reservoirs are attractive candidates for CO2 flooding due to the size of the initial oil deposits; however recoveries due to the strong waterdrive and good quality sands often result in low residual and/or remaining oil saturations. With oil zone thickness often exceeding 100 feet, significant challenges exist in developing optimum completion strategy and pattern selection. For the Hastings CO2 flood, five-spot injection patterns will be staggered so that the upper and lower portions of the reservoir have dedicated injectors and producers, thus improving vertical sweep. Water injection profiles have also shown that perforation shot density is key to insuring uniform vertical sweep given the minimal pressure drop across each perforation when low viscosity CO2 is injected. Reservoir pressure within the floodable area must also be maintained (preventing leakoff) in order to maximize displacement efficiency. This is accomplished by use of water injection wells placed downdip to act as a water curtain, thus reducing leakoff of pressure into the infinite acting aquifer. As expansion of the EOR project develops additional patterns downdip, water injectors will be placed further downdip, while the updip injectors will be placed on CO2.
a b s t r a c tOne means of producing a 3D current in a circular tank is by using groups of conditioned axial flow impellers arranged around the perimeter to collectively create a sea representative bulk flow in a laboratory setting. Unfortunately to achieve the required bulk flow neighbouring impellers have to operate at different speeds resulting in steps in the plan view velocity profile. Therefore the underlying situation that governs tank behaviour is that of two fluid streams at different speeds combining, leading to a turbulent mixing layer which then dissipates and develops. Here a simulation of this flow is created using a 2D Reynolds Averaged Navier-Stokes method and then validated with physical experiments. The implications for accuracy and computational costs of various turbulence models, boundary conditions setups, and geometry representations are assessed. These findings are then used to produce a simplified 2D numerical model of the plan view flows in a 3D test tank which is then employed to demonstrate how a satisfactory device test zone might be generated from groups of stepped inputs. This finding helps prove that a combined current and wave tank can be created using the described configuration with the model providing a useful means of testing control scenarios.
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