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Title: Bonneville Powerhouse 2 Fish Guidance Efficiency Studies: CFD Model of the Forebay

Abstract

In ongoing work, U.S. Army Corps of Engineers, Portland District (CENWP) is seeking to better understand and improve the conditions within the Bonneville Powerhouse 2 (B2) turbine intakes to improve survival of downstream migrant salmonid smolt. In this study, the existing B2 forebay computational fluid dynamics (CFD) model was modified to include a more detailed representation of all B2 turbine intakes. The modified model was validated to existing field-measured forebay ADCP velocities. The initial CFD model scenarios tested a single project operation and the impact of adding the Behavior Guidance System (BGS) or Corner Collector. These structures had impacts on forebay flows. Most notable was that the addition of the BGS and Corner Collector reduced the lateral extent of the recirculation areas on the Washington shore and Cascade Island and reduced the flow velocity parallel to the powerhouse in front of Units 11 and 12. For these same cases, at the turbine intakes across the powerhouse, there was very little difference in the flow volume into the gatewell for the clean forebay, and the forebay with the BGS in place and/or the Corner Collector operating. The largest differences were at Units 11 to 13. The CFD model cases testing themore » impact of the gatewell slot fillers showed no impact to the forebay flows, but large differences within the gatewells. With the slot fillers, the flow above the standard traveling screen and into the gatewell increased (about 100 cfs at each turbine intake) and the gap flow decreased across the powerhouse for all cases. The increased flow up the gatewell was further enhanced with only half the units operating. The flow into the gatewell slot was increased about 35 cfs for each bay of each intake across the powerhouse; this change was uniform across the powerhouse. The flows in the gatewell of Unit 12, the most impacted unit for the scenarios, was evaluated. In front of the vertical barrier screen, the CFD model with slot fillers showed reduced the maximum velocities (in spite of the increased the flow into the gatewell), and decreased the area of recirculation. The area near the VBS exceeding the normal velocity criteria of 1 ft/s was reduced and the flows were more balanced.« less

Authors:
; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1059042
Report Number(s):
PNNL-21420
400403209
DOE Contract Number:
AC05-76RL01830
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
computational fluid dynamics, salmon passage, Bonneville,

Citation Formats

Rakowski, Cynthia L., Serkowski, John A., and Richmond, Marshall C.. Bonneville Powerhouse 2 Fish Guidance Efficiency Studies: CFD Model of the Forebay. United States: N. p., 2012. Web. doi:10.2172/1059042.
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Rakowski, Cynthia L., Serkowski, John A., & Richmond, Marshall C.. Bonneville Powerhouse 2 Fish Guidance Efficiency Studies: CFD Model of the Forebay. United States. doi:10.2172/1059042.
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Rakowski, Cynthia L., Serkowski, John A., and Richmond, Marshall C.. Sun . "Bonneville Powerhouse 2 Fish Guidance Efficiency Studies: CFD Model of the Forebay". United States. doi:10.2172/1059042. https://www.osti.gov/servlets/purl/1059042.
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@article{osti_1059042,
title = {Bonneville Powerhouse 2 Fish Guidance Efficiency Studies: CFD Model of the Forebay},
author = {Rakowski, Cynthia L. and Serkowski, John A. and Richmond, Marshall C.},
abstractNote = {In ongoing work, U.S. Army Corps of Engineers, Portland District (CENWP) is seeking to better understand and improve the conditions within the Bonneville Powerhouse 2 (B2) turbine intakes to improve survival of downstream migrant salmonid smolt. In this study, the existing B2 forebay computational fluid dynamics (CFD) model was modified to include a more detailed representation of all B2 turbine intakes. The modified model was validated to existing field-measured forebay ADCP velocities. The initial CFD model scenarios tested a single project operation and the impact of adding the Behavior Guidance System (BGS) or Corner Collector. These structures had impacts on forebay flows. Most notable was that the addition of the BGS and Corner Collector reduced the lateral extent of the recirculation areas on the Washington shore and Cascade Island and reduced the flow velocity parallel to the powerhouse in front of Units 11 and 12. For these same cases, at the turbine intakes across the powerhouse, there was very little difference in the flow volume into the gatewell for the clean forebay, and the forebay with the BGS in place and/or the Corner Collector operating. The largest differences were at Units 11 to 13. The CFD model cases testing the impact of the gatewell slot fillers showed no impact to the forebay flows, but large differences within the gatewells. With the slot fillers, the flow above the standard traveling screen and into the gatewell increased (about 100 cfs at each turbine intake) and the gap flow decreased across the powerhouse for all cases. The increased flow up the gatewell was further enhanced with only half the units operating. The flow into the gatewell slot was increased about 35 cfs for each bay of each intake across the powerhouse; this change was uniform across the powerhouse. The flows in the gatewell of Unit 12, the most impacted unit for the scenarios, was evaluated. In front of the vertical barrier screen, the CFD model with slot fillers showed reduced the maximum velocities (in spite of the increased the flow into the gatewell), and decreased the area of recirculation. The area near the VBS exceeding the normal velocity criteria of 1 ft/s was reduced and the flows were more balanced.},
doi = {10.2172/1059042},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jul 01 00:00:00 EDT 2012},
month = {Sun Jul 01 00:00:00 EDT 2012}
}
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DOI:  10.2172/1059042
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  • ; ;
    In 2008 and 2009, a 700 ft long, 10-ft deep floating forebay guidance wall called a behavioral guidance structure (BGS) was deployed in the Bonneville Powerhouse 2 forebay. The US Army Corps of Engineers, Portland District (CENWP) contracted with the Pacific Northwest National Laboratory (PNNL) to develop computational tools to assess the impact of the BGS on forebay hydraulics (this study). The tools developed here to provide a characterization of forebay hydraulics to be integrated with acoustic telemetry studies designed to measure the impact on juvenile salmon guidance and survival through Bonneville Powerhouse 2. In previous work, PNNL performed computationalmore » fluid dynamics (CFD) studies for the Bonneville forebay for CENWP. In this study, the existing model was modified to include the BGS. The model included a bay-by-bay spillway, a truncated Powerhouse 1 forebay, Powerhouse 2 turbine intakes and corner collector, and the forebay bathymetry extending approximately 1.5km upstream from the tip of Cascade Island. Model validation outcomes were similar to that of past studies. Additional checks were included on the impact of the differencing scheme to flow solution. It was found that using upwind differencing was adequate and it was possible to use a truncated computational mesh of this model that included a BGS upstream of Powerhouse 2 and increased spatial resolution in the vicinity of the BGS. This model has been validated, run, and provided to CENWP to use for additional analysis of the Powerhouse 2 forebay hydraulics. The PNNL particle tracking software (PT6) was used to assess the impacts of mass and relative buoyancy on particle fate. The particle tracker was run for the Half Load case for the clean forebay and for the forebay with the BGS in place and the Corner Collector on. All tracker cases showed that the BGS moved the particles across the forebay increasing the number of particles exiting the model through the Corner Collector and (for streamlines and neutrally-buoyant particles) the lower numbered turbine units.« less

  • ;
    The goal of the study described in this report is to provide U.S. Army Corps of Engineers (USACE) biologists and engineers with general design guidelines for using artificial lighting to enhance the passage of juvenile salmonids into the collection channel at the Bonneville Dam second powerhouse (B2). During fall 2007, Pacific Northwest National Laboratory (PNNL) researchers measured light levels in the field at one powerhouse orifice through which fish must pass to reach the collection channel. Two light types were evaluated—light-emitting diode (LED) lights and halogen spot lights. Additional measurements with mercury lamps were made at the PNNL Aquatic Researchmore » Laboratory to determine baseline intensity of the current lighting. A separate chapter synthesizes the relevant literature related to light and fish guidance for both field and laboratory studies. PNNL will also review the Corps plans for existing lighting protocol at all of the Portland District projects and help develop a uniform lighting scheme which could be implemented. The specific objectives for this study are to 1. Create a synthesis report of existing lighting data for juvenile salmonid attraction and deterrence and how the data are used at fish bypass facilities. 2. Evaluate current B2 orifice lighting conditions with both LED and halogen sources. 3. Make recommendations as to what lighting intensity, source, and configuration would improve passage at the B2 orifices. 4. Review USACE plans for retrofit of existing systems (to be assessed at a later date).« less

  • ; ; ; ...
    Summarizes research conducted at Bonneville Dam in 2008 to evaluate a prototype Behavioral Guidance Structure, that was deployed by the US Army Corps of Engineers in an effort to increase survival of outmigrating smolts at Bonneville Dam.

  • ; ;
    This report was prepared by the Pacific Northwest National Lab., Richland, Washington, BAE Systems, Inc., a subcontractor to the U.S. Army Engineer Research and Development Center (ERDC), Vicksburg, Mississippi. This study examined the effect of gatewell modifications on the proportion of fish lost through the gap between the top of submerged traveling screens (STSs) and the ceilings of intakes in one un-modified and two modified turbine units at Bonneville Dam Second Powerhouse (B2). Combined modifications reduced the proportion of flow through the gap from 44% to 16% and increased the proportion moving up the gatewell from 56% to 84%. Wemore » used a Dual-Frequency Identification Sonar (DIDSON) acoustic camera to record proportions of juvenile salmonids moving up into the gatewell and through the gap. The acoustic camera was used to record images of fish passing up into the gatewell and through the gap for 8-h on three successive nights in every intake of units 13, 15, and 17 (i.e., 9 intakes x 3 nights = 27 nights each season). Only 28.6% of the objects detected in spring and 12.9% in summer were determined to be fish. Other objects included sticks and debris. Although the true magnitude of STS gap-loss is unknown, both acoustic camera and netting estimates indicate that gatewell modifications reduce relative gap loss by about 67%.« less

  • A second powerhouse at the existing Bonneville Dam project was constructed to take advantage of additional upriver storage provided through treaty agreements with Canada. Hydraulic model studies were accomplished to evaluate hydraulic performance with various powerhouse locations. A new navigation lock is proposed for the project. Although the lock was not studied in this investigation, a primary powerhouse design consideration was that the second powerhouse location must not conflict with the logical location of a new navigation lock. A 1:100-scale model was used to study flow conditions in the forebay and tail-race of the powerhouse and to evaluate the effectmore » of the powerhouse on existing fishway and navigation facilities. Three powerhouse locations were studied in the model; however, the final design consisted of an eight-unit powerhouse located on the north (Washington) shore. Tests indicated that raising the tailrace invert to elevation -10 could not be justified due to excessive power loss which would occur with this condition.« less