ASDSO Dam Safety Toolbox

Hydraulics: Difference between revisions

From ASDSO Dam Safety Toolbox
Jump to: navigation, search
No edit summary
No edit summary
 
(23 intermediate revisions by 6 users not shown)
Line 5: Line 5:
| [[Image:CFD1.png|800px|x800px|link=Outlet Configuration]]
| [[Image:CFD1.png|800px|x800px|link=Outlet Configuration]]
|-
|-
|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).
|}
|}


Line 18: Line 19:
* [[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 (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"/>
“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}} [[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, 2022]]
{{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}} [[Technical Release 210-60: Earth Dams and Reservoirs | Technical Release 210-60: Earth Dams and Reservoirs, NRCS, 2019]]
{{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, 2013]]
{{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}} [[Selecting and Accommodating Inflow Design Floods for Dams (FEMA P-94) | Selecting and Accommodating Inflow Design Floods for Dams (FEMA P-94), FEMA, 2013]]
{{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 Spillways (EM 1110-2-1603) | Hydraulic Design of Spillways (EM 1110-2-1603), USACE, 1992]]
{{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, 1987]]
{{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, 1980]]
{{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==
Line 48: Line 59:




{|  class="wikitable" style="margin:auto" style="background-color:#F0F8FF" style="border-style: none;"
|colspan="3"; style="text-align:left;"|'''This page is maintained by the following ASDSO volunteers:'''
|-
|'''Subject Matter Expert:'''
|Paul Schweiger, P.E.   
|-
|'''Web Editor:'''
|Riley Manwaring 
|}




<!-- Revision history information -->
<!-- Revision history information -->
{{revhistinf}}
{{revhistinf}}

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 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]

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

Design Standards No. 14: Appurtenant Structures for Dams (Ch. 3: General Spillway Design Considerations), USBR

Technical Release 210-60: Earth Dams and Reservoirs, NRCS

Federal Guidelines for Inundation Mapping of Flood Risks Associated with Dam Incidents and Failures (FEMA P-946), FEMA

Selecting and Accommodating Inflow Design Floods for Dams (FEMA P-94), FEMA

Hydraulic Design of Spillways (EM 1110-2-1603), USACE

Design of Small Dams, USBR

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