Cynthia L. Rakowski
Pacific Northwest National Laboratory
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Featured researches published by Cynthia L. Rakowski.
Archive | 2005
Gary E. Johnson; Michael E. Hanks; Fenton Khan; Christopher B. Cook; John Hedgepeth; Robert P. Mueller; Cynthia L. Rakowski; Marshall C. Richmond; Susan L. Sargeant; John A. Serkowski; John R. Skalski
The U.S. Army Corps of Engineers Portland District engaged the Pacific Northwest National Laboratory to evaluate juvenile salmon passage at The Dalles Dam in 2004 to inform decisions about long-term measures and operations to enhance sluiceway and spill passage and reduce turbine passage to improve smolt survival at the dam. PNNL used fixed-location hydroacoustic sampling across the entire project, especially at the sluiceway and spillway, using multiple split-beam transducers at selected locations. At the sluiceway nearfield, we used an acoustic camera to track fish. The fish data were interpreted and integrated with hydraulic data from a CFD model and in-field ADCP measurements. Two sluiceway operations were compared: West only (SL 1) vs. West+East (SL 1 + SL 18). Based on our findings, we concluded that The Dalles Dam sluiceway has the potential to be highly efficient and effective at passing juvenile salmonids. This potential could be tapped with hydraulic and entrance enhancements to the sluiceway. We recommended the following: (1) six rather than three sluice gates should be opened to take advantage of the maximum hydraulic capacity of the sluiceway. (2) The turbine units below open sluice gates should be operated as a standard fish operations procedure. (3) In 2005, the Corps and fisheries agencies should consider operating sluice gates in one or more of the following combinations of six gates: (a) SL 1-1, 1-2, 1-3 and SL 18-1, 18-2, 18-3 (repeat 2004 operation), (b) SL 1-1, 1-2, 1-3 and SL 11-1, 11-2, 11-3, or (c) SL 1-1, 1-2, 1-3 and SL 2-1, 2-2, 2-3. The following elements for surface flow bypasses which should be considered during design of any sluiceway enhancements at The Dalles Dam: (1) form an extensive surface flow bypass flow net (surface bypass discharge greater than {approx}7% of total project discharge), (2) create a gradual increase in water velocity approaching the surface flow bypass (ideally, acceleration 3 m/s) to entrain the subject juvenile fishes, (4) adapt the shape and orientation of the surface entrance(s) to fit site-specific features, and (5) consider installing a forebay wall to increase fish availability to the surface flow bypass.
Archive | 2009
Gary E. Johnson; Marshall C. Richmond; John Hedgepeth; Gene R. Ploskey; Michael G. Anderson; Zhiqun Deng; Fenton Khan; Robert P. Mueller; Cynthia L. Rakowski; Nichole K. Sather; John A. Serkowski; John R. Steinbeck
This study provides information on juvenile salmonid behaviors at McNary and The Dalles dams that can be used by the USACE, fisheries resource managers, and others to support decisions on long-term measures to enhance fish passage. We researched smolt movements and ambient hydrodynamic conditions using a new approach combining simultaneous acoustic Doppler current profiler (ADCP) and acoustic imaging device (AID) measurements at surface flow outlets (SFO) at McNary and The Dalles dams on the Columbia River during spring and summer 2007. Because swimming effort vectors could be computed from the simultaneous fish and flow data, fish behavior could be categorized as passive, swimming against the flow (positively rheotactic), and swimming with the flow (negatively rheotactic). We present bivariate relationships to provide insight into fish responses to particular hydraulic variables that engineers might consider during SFO design. The data indicate potential for this empirical approach of simultaneous water/fish measurements to lead to SFO design guidelines in the future.
World Water and Environmental Resources Congress 2004 | 2004
Cynthia L. Rakowski; Laurie L. Ebner; Marshall C. Richmond
A set of three-dimensional, computational fluid dynamics (CFD) models were developed and used for the Bonneville Project tailrace to study the impact of a proposed outfall structure on the tailrace hydraulics; these structures were designed to improve the survival of downstream migrant (juvenile) salmon. Flows were simulated by solving the Reynolds-Averaged Navier-Stokes equations together with a two-equation k-epsilon turbulences model in a commercial CFD code. The numerical model was validated using field-measured velocity data. The model results identified undesirable combinations of outfall location and operational scenarios and helped to identify the location in which the outfall structure was built. The numerical model provided a relatively low-cost tool to rapidly simulate and visualize the flow field for multiple proposed outfall locations for a large number of operational scenarios. The visualizations of the results from the CFD model provided insights to hydraulic engineers and fisheries biologists working on the design and placement of the outfall structure.
Archive | 2010
Marshall C. Richmond; Cynthia L. Rakowski; William A. Perkins; John A. Serkowski
Computational fluid dynamics (CFD) simulations of turbulent flow and particle motion are being conducted to evaluate the frequency and severity of collisions between marine and hydrokinetic (MHK) energy devices and debris or aquatic organisms. The work is part of a collaborative research project between Pacific Northwest National Laboratory (PNNL) and Sandia National Laboratories , funded by the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Wind and Water Power Program. During FY2010 a reference design for an axial flow MHK turbine was used to develop a computational geometry for inclusion into a CFD model. Unsteady simulations of turbulent flow and the moving MHK turbine blades are being performed and the results used for simulation of particle trajectories. Preliminary results and plans for future work are presented.
Archive | 2006
Cynthia L. Rakowski; Marshall C. Richmond; John A. Serkowski
A computational fluid dynamics (CFD) model was used in an investigation into the suppression of a surface vortex that forms and the south-most spilling bay at The Dalles Project. The CFD work complemented work at the prototype and the reduced-scale physical models. The CFD model was based on a model developed for other work in the forebay but had additional resolution added near the spillway. Vortex suppression devices (VSDs) were to placed between pier noses and/or in the bulkhead slot of the spillway bays. The simulations in this study showed that placing VSD structures or a combination of structures to suppress the vortex would still result in near-surface flows to be entrained in a vortex near the downstream spillwall. These results were supported by physical model and prototype studies. However, there was a consensus of the fish biologists at the physical model that the fish would most likely move north and if the fish went under the VSD it would immediately exit the forebay through the tainter gate and not get trapped between VSDs or the VSDs and the tainter gate if the VSDs were deep enough.
Archive | 2015
Marshall C. Richmond; Pedro Romero-Gomez; John A. Serkowski; Cynthia L. Rakowski; Michael J. Graf
....................................................................................................................................................... iii Acknowledgments ..........................................................................................................................................v Acronyms and Abbreviations ...................................................................................................................... vii 1.0 Introduction ............................................................................................................................................1 2.0 The Biological Performance Assessment Method .................................................................................3 2.1 BioPA Assumptions ......................................................................................................................4 3.0 Wanapum Dam ......................................................................................................................................5 4.0 The Sensor Fish .....................................................................................................................................5 5.0 Computational Fluid Dynamics Simulations .........................................................................................7 6.0 Streamtrace Seeding and Seed Weighting .............................................................................................9 7.0 Results and Discussion ........................................................................................................................12 8.0 Summary and Conclusions ..................................................................................................................21 9.0 References ............................................................................................................................................24
Archive | 2014
John Gasper; Thomas D. Veselka; Matthew Mahalik; John W. Hayse; Samrat Saha; Mark S. Wigmosta; Nathalie Voisin; Cynthia L. Rakowski; Andre M. Coleman; Thomas S. Lowry
This report summarizes the results of the development and demonstration phase of the Water Use Optimization Toolset (WUOT) project. It identifies the objective and goals that guided the project, as well as demonstrating potential benefits that could be obtained by applying the WUOT in different geo-hydrologic systems across the United States. A major challenge facing conventional hydropower plants is to operate more efficiently while dealing with an increasingly uncertain water-constrained environment and complex electricity markets. The goal of this 3-year WUOT project, which is funded by the U.S. Department of Energy (DOE), is to improve water management, resulting in more energy, revenues, and grid services from available water, and to enhance environmental benefits from improved hydropower operations and planning while maintaining institutional water delivery requirements. The long-term goal is for the WUOT to be used by environmental analysts and deployed by hydropower schedulers and operators to assist in market, dispatch, and operational decisions.
Archive | 2010
Cynthia L. Rakowski; John A. Serkowski; Marshall C. Richmond
The US Army Corps of Engineers Portland District (CENWP) has developed a computational fluid dynamics (CFD) model of the John Day forebay on the Columbia River to aid in the development and design of alternatives to improve juvenile salmon passage at the John Day Project. At the request of CENWP, Pacific Northwest National Laboratory (PNNL) Hydrology Group has conducted a technical review of CENWPs CFD model run in CFD solver software, STAR-CD. PNNL has extensive experience developing and applying 3D CFD models run in STAR-CD for Columbia River hydroelectric projects. The John Day forebay model developed by CENWP is adequately configured and validated. The model is ready for use simulating forebay hydraulics for structural and operational alternatives. The approach and method are sound, however CENWP has identified some improvements that need to be made for future models and for modifications to this existing model.
Archive | 2010
Cynthia L. Rakowski; John A. Serkowski; Marshall C. Richmond
The U.S. Army Corps of Engineers-Portland District (CENWP) has ongoing work to improve the survival of juvenile salmonids (smolt) migrating past The Dalles Dam. As part of that effort, a spillwall was constructed to improve juvenile egress through the tailrace downstream of the stilling basin. The spillwall was designed to improve smolt survival by decreasing smolt retention time in the spillway tailrace and the exposure to predators on the spillway shelf. The spillwall guides spillway flows, and hence smolt, more quickly into the thalweg. In this study, an existing computational fluid dynamics (CFD) model was modified and used to characterize tailrace hydraulics between the new spillwall and the Washington shore for six different total river flows. The effect of spillway flow distribution was simulated for three spill patterns at the lowest total river flow. The commercial CFD solver, STAR-CD version 4.1, was used to solve the unsteady Reynolds-averaged Navier-Stokes equations together with the k-epsilon turbulence model. Free surface motion was simulated using the volume-of-fluid (VOF) technique. The model results were used in two ways. First, results graphics were provided to CENWP and regional fisheries agency representatives for use and comparison to the same flow conditions at a reduced-scale physical model. The CFD results were very similar in flow pattern to that produced by the reduced-scale physical model but these graphics provided a quantitative view of velocity distribution. During the physical model work, an additional spill pattern was tested. Subsequently, that spill pattern was also simulated in the numerical model. The CFD streamlines showed that the hydraulic conditions were likely to be beneficial to fish egress at the higher total river flows (120 kcfs and greater, uniform flow distribution). At the lowest flow case, 90 kcfs, it was necessary to use a non-uniform distribution. Of the three distributions tested, splitting the flow evenly between Bay 7 and Bay 8 had hydraulics deemed most beneficial for egress by CENWP fisheries biologists and regional fishery agency representatives. The numerical and physical model results were very similar, building confidence in both hydraulic tools.
Archive | 2008
Cynthia L. Rakowski; William A. Perkins; Marshall C. Richmond; John A. Serkowski
This report presents results of a computational fluid dynamics (CFD) modeling study to evaluatethe impacts of a full-length spillwall at The Dalles Dam. The full-length spillwall is being designed and evaluated as a structural means to improve tailrace egress and thus survival of juvenile fish passing through the spillway. During the course of this study, a full-length spillwall at Bays 6/7 and 8/9 were considered. The U.S. Army Corps of Engineers (USACE) has proposed extending the spillwall constructed in the stilling basin between spillway Bays 6 and 7 about 590 ft farther downstream. It is believed that the extension of the spillwall will improve egress conditions for downstream juvenile salmonids by moving them more rapidly into the thalweg of the river hence reducing their exposure to predators. A numerical model was created, validated, and applied the The Dalles Dam tailrace. The models were designed to assess impacts to flow, tailrace egress, navigation, and adult salmon passage of a proposed spill wall extension. The more extensive model validation undertaken in this study greatly improved our confidence in the numerical model to represent the flow conditions in The Dalles tailrace. This study used these validated CFD models to simulate the potential impacts of a spillwall extension for The Dalles Dam tailrace for two locations. We determined the following: (1)The construction of an extended wall (between Bays 6/7) will not adversely impact entering or exiting the navigation lock. Impact should be less if a wall were constructed between Bays 8/9. (2)The construction of a wall between Bays 6/7 will increase the water surface elevation between the wall and the Washington shore. Although the increased water surface elevation would be beneficial to adult upstream migrants in that it decreases velocities on the approach to the adult ladder, the increased flow depth would enhance dissolved gas production, impacting potential operations of the project because of water quality. A wall between Bays 8/9 should have a lesser impact as the confined spill would be across more bays and the relative flow constriction less. (3) The 405 kcfs case was used for the rapid assessment of flow conditions and hydraulic mechanisms that might be responsible for the unexpected erosion at the end of the shelf downstream of Bay 7.