Hydraulics: Difference between revisions
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| [[Image:CFD1.png|800px|x800px|link=Outlet Configuration]] | | [[Image:CFD1.png|800px|x800px|link=Outlet Configuration]] | ||
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|style="text-align:center; font-size:90%;"| Analysis of spillway hydraulics using Computational Fluid Dynamics (CFD). | |style="text-align:center; font-size:90%;"| Analysis of spillway hydraulics using [[Computational Fluid Dynamics (CFD)]]. CFD can be used to model three-dimensional hydraulic conditions (such as the standing waves downstream of the control section in this picture) that are important in evaluating spillway capacity and the adequacy of spillway training walls | ||
(Image Source: Gannett Fleming). | |||
|} | |} | ||
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The hydraulic design of a dam includes a knowledge of | The hydraulic design of a dam includes a knowledge of the following foundational topics: pressurized and free-surface flow, uniform flow, gradually and rapidly varied flow, steady and unsteady flow, energy and momentum principles, energy losses, and [[cavitation]]. <ref name ="USACE">[[Hydraulic Design of Spillways (EM 1110-2-1603) | Hydraulic Design of Spillways (EM 1110-2-1603), USACE, 1992]]</ref> | ||
==Types of Evaluations== | ==Types of Evaluations== | ||
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* [[Erosion & Scour Mitigation]] | * [[Erosion & Scour Mitigation]] | ||
* [[Tailwater Modeling]] | * [[Tailwater Modeling]] | ||
==Hydraulic Calculation Methods== | |||
Several calculation methods have been developed to represent various hydraulic flow conditions. Some of these methods are founded in theory, such as the Bernoulli Equation which represents the conservation of energy within a non-compressible fluid in motion. Others are empirical in nature. These types of equations are based on observations and experience as opposed to theoretical relationships. Hydraulic calculation methods include the following: | |||
* [[Open Channel Flow]] | |||
* [[Orifice Flow]] | |||
* [[Weir Flow]] | |||
* [[Pipe Flow]] | |||
==Types of Hydraulic Modeling== | ==Types of Hydraulic Modeling== | ||
Selection of either a one-, two-, or three-dimensional hydraulic model is necessary depending on both the complexity of the flow conditions and the level of accuracy required of the model. Hydraulic modeling helps to attain a higher-optimized level of operation of the dam and reduce uncertainty. | Hydraulic conditions are often quite complex and difficult to represent using simple mathematical routines. In these cases, numerical models and computer programs have been developed to solve these complex hydraulic computations. Selection of either a one-, two-, or three-dimensional hydraulic model is necessary depending on both the complexity of the flow conditions and the level of accuracy required of the model. Hydraulic modeling helps to attain a higher-optimized level of [[operation]] of the dam and reduce uncertainty. | ||
“Maintaining the high efficiency of a spillway requires careful design of the spillway crest, the approach configuration, and the piers and abutments. For this reason, when design considerations require departure from established design data, model studies of the spillway system should be accomplished”. | “Maintaining the high efficiency of a spillway requires careful design of the spillway crest, the approach configuration, and the piers and abutments. For this reason, when design considerations require departure from established design data, model studies (or three-dimensional computer models) of the spillway system should be accomplished”. Physical model studies or three-dimensional [[Computational Fluid Dynamics (CFD)]] models are recommended to confirm any design that involves complex geometric considerations and/or large discharges and velocities. <ref name ="USACE"/> | ||
* [[One-Dimensional Hydraulic Models]] | * [[One-Dimensional Hydraulic Models]] | ||
* [[Two-Dimensional Hydraulic Models]] | * [[Two-Dimensional Hydraulic Models]] | ||
* [[Three-Dimensional Hydraulic Models]] | * [[Three-Dimensional Hydraulic Models]] | ||
* [[Physical Models]] | |||
A critical aspect of any [[engineering]] analysis is communication. There are a variety of hydraulic modeling approaches and methodologies, and it is important to owners, consultants, and regulators that clear communication is integrated in the process. General guidance and recommendations regarding both pre- and post-modeling communication are provided on this page: [[Modeling Communication]]. Items specific to hydraulic analysis that should be considered in advance of any modeling effort are summarized here: [[Pre-Modeling Communication: Hydraulic Model Considerations]]. | |||
==Best Practices Resources== | ==Best Practices Resources== | ||
{{Document Icon}} [[Federal Guidelines for Inundation Mapping of Flood Risks Associated with Dam Incidents and Failures (FEMA P-946)|Federal Guidelines for Inundation Mapping of Flood Risks Associated with Dam Incidents and Failures (FEMA P-946) | {{Document Icon}} [[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 3: General Spillway Design Considerations) | Design Standards No. 14: Appurtenant Structures for Dams (Ch. 3: General Spillway Design Considerations), USBR]] | ||
{{Document Icon}} [[Selecting and Accommodating Inflow Design Floods for Dams (FEMA P-94)|Selecting and Accommodating Inflow Design Floods for Dams (FEMA P-94) | {{Document Icon}} [[Technical Release 210-60: Earth Dams and Reservoirs | Technical Release 210-60: Earth Dams and Reservoirs, NRCS]] | ||
{{Document Icon}} [[Federal Guidelines for Inundation Mapping of Flood Risks Associated with Dam Incidents and Failures (FEMA P-946) | Federal Guidelines for Inundation Mapping of Flood Risks Associated with Dam Incidents and Failures (FEMA P-946), FEMA]] | |||
{{Document Icon}} [[Hydraulic Design of Spillways (EM 1110-2-1603)|Hydraulic Design of Spillways (EM 1110-2-1603) | {{Document Icon}} [[Selecting and Accommodating Inflow Design Floods for Dams (FEMA P-94) | Selecting and Accommodating Inflow Design Floods for Dams (FEMA P-94), FEMA]] | ||
{{Document Icon}} [[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602)|Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) | {{Document Icon}} [[Hydraulic Design of Spillways (EM 1110-2-1603) | Hydraulic Design of Spillways (EM 1110-2-1603), USACE]] | ||
{{Document Icon}} [[Design of Small Dams | Design of Small Dams, USBR]] | |||
{{Document Icon}} [[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) | Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602), USACE]] | |||
==Trainings== | ==Trainings== | ||
{{Video Icon}} [[On-Demand Webinar: Hydraulics 101: Intro to Hydraulics for Dam Safety]] | |||
{{Video Icon}} [[On-Demand Webinar: Hydraulics 201 for Dam Safety]] | |||
{{Video Icon}} [[On-Demand Webinar: Inlet and Outlet Hydraulics for Spillways and Outlet Structures]] | {{Video Icon}} [[On-Demand Webinar: Inlet and Outlet Hydraulics for Spillways and Outlet Structures]] | ||
{{Video Icon}} [[On-Demand Webinar: Designing Spillways to Mitigate Failure Modes]] | {{Video Icon}} [[On-Demand Webinar: Designing Spillways to Mitigate Failure Modes]] | ||
{{Video Icon}} [[On-Demand Webinar: Introduction to Addressing Inadequate Conveyance Capacity at Dams]] | {{Video Icon}} [[On-Demand Webinar: Introduction to Addressing Inadequate Conveyance Capacity at Dams]] | ||
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{{Citations}} | {{Citations}} | ||
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Latest revision as of 19:42, 27 August 2024
|
| Analysis of spillway hydraulics using Computational Fluid Dynamics (CFD). CFD can be used to model three-dimensional hydraulic conditions (such as the standing waves downstream of the control section in this picture) that are important in evaluating spillway capacity and the adequacy of spillway training walls
(Image Source: Gannett Fleming). |
The hydraulic design of a dam includes a knowledge of the following foundational topics: pressurized and free-surface flow, uniform flow, gradually and rapidly varied flow, steady and unsteady flow, energy and momentum principles, energy losses, and cavitation. [1]
Types of Evaluations
- Hydraulic Performance of Spillways
- Hydraulic Performance of Outlet Works
- Dam Breach Inundation Analysis
- Spillway Integrity Analysis
- Erosion & Scour Mitigation
- Tailwater Modeling
Hydraulic Calculation Methods
Several calculation methods have been developed to represent various hydraulic flow conditions. Some of these methods are founded in theory, such as the Bernoulli Equation which represents the conservation of energy within a non-compressible fluid in motion. Others are empirical in nature. These types of equations are based on observations and experience as opposed to theoretical relationships. Hydraulic calculation methods include the following:
Types of Hydraulic Modeling
Hydraulic conditions are often quite complex and difficult to represent using simple mathematical routines. In these cases, numerical models and computer programs have been developed to solve these complex hydraulic computations. Selection of either a one-, two-, or three-dimensional hydraulic model is necessary depending on both the complexity of the flow conditions and the level of accuracy required of the model. Hydraulic modeling helps to attain a higher-optimized level of operation of the dam and reduce uncertainty.
“Maintaining the high efficiency of a spillway requires careful design of the spillway crest, the approach configuration, and the piers and abutments. For this reason, when design considerations require departure from established design data, model studies (or three-dimensional computer models) of the spillway system should be accomplished”. Physical model studies or three-dimensional Computational Fluid Dynamics (CFD) models are recommended to confirm any design that involves complex geometric considerations and/or large discharges and velocities. [1]
- One-Dimensional Hydraulic Models
- Two-Dimensional Hydraulic Models
- Three-Dimensional Hydraulic Models
- Physical Models
A critical aspect of any engineering analysis is communication. There are a variety of hydraulic modeling approaches and methodologies, and it is important to owners, consultants, and regulators that clear communication is integrated in the process. General guidance and recommendations regarding both pre- and post-modeling communication are provided on this page: Modeling Communication. Items specific to hydraulic analysis that should be considered in advance of any modeling effort are summarized here: Pre-Modeling Communication: Hydraulic Model Considerations.
Best Practices Resources
Technical Release 210-60: Earth Dams and Reservoirs, NRCS
Selecting and Accommodating Inflow Design Floods for Dams (FEMA P-94), FEMA
Hydraulic Design of Spillways (EM 1110-2-1603), USACE
Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602), USACE
Trainings
On-Demand Webinar: Hydraulics 101: Intro to Hydraulics for Dam Safety
On-Demand Webinar: Hydraulics 201 for Dam Safety
On-Demand Webinar: Inlet and Outlet Hydraulics for Spillways and Outlet Structures
On-Demand Webinar: Designing Spillways to Mitigate Failure Modes
On-Demand Webinar: Introduction to Addressing Inadequate Conveyance Capacity at Dams
Citations:
Revision ID: 8036
Revision Date: 08/27/2024