The widespread applications of fluid mechanics and hydraulics in civil engineering include transportation of fluids in pipes and in open channels, as well as flow measurement for both pipes and open channels. It is almost impossible to make froude number and reynolds number identical in model and prototype. Mike 11 of the danish hydraulic institute software and hecras. In scale models, should froude number or reynolds number be. Froude number equations formulas calculator open channel flow fluid mechanics hydraulics. Chapter 6 stream hydraulics figure 619 profile for crest of log weir problem 626 figure 620 determination of jump length based on upstream 631 froude number figure 621 parameters involved with modeling a hydraulic 631 jump. The sequentdepth ratio in a hydraulic jump formed in a horizontal rectangular channel is 16. Basic hydraulic principles of openchannel flow by harvey e. Nine tests were conducted at steady flow conditions with approach flow froude numbers of fo. These areas of application use a variety of calculations for design and for analysis. Force due to gravity is predominant in open hydraulic structures such as spillways, open channel flow.
The dimensionless quantity ugl12, where u is a characteristic velocity of flow, g is the acceleration of gravity, and l is a characteristic length. Open channel design example 1c a trapezoidal channel carrying 11. Applications of the bernoulli equation to open channel flows. Reynolds number is adopted when viscous forces are predominant in the channel flow. It is the ratio of kinetic to potential energy, and is used to characterize open channel flow. Froude number equations formulas calculator aj design software. Performs civil engineering calculations for hydrology, open channels, culverts, gravity sewer, transmission lines and unit conversions. Froude number fr, in hydrology and fluid mechanics, dimensionless quantity used to indicate the influence of gravity on fluid motion. Open channel flow section parameters reach length l l arbitrary horizontal distance between two crosssections bed slope so ll dzdx z2z1l tanq flow depth y l vertical distance from channel bottom to free water surface. With the setting froude number equal to 1 in the trapezoidal channels and the insertion.
The froude number of a subcritical stream at the end of a hydraulic jump in a horizontal rectangular channel is 0. Estimates open channel flow pressureplusmomentum balance for pipeflow junctions. Dec 14, 2016 open channel hydraulics types of flow in open channels subcritical, critical and supercritical flow. Openchannel flow, a branch of hydraulics and fluid mechanics, is a type of liquid flow within a conduit with a free surface, known as a channel.
Depth of flow is higher than y c, f 1, momentum dominates supercritical. The froude number assumes a special role in openchannel flow because. The froude number, fr, is a dimensionless value that describes different flow regimes of open channel flow. Open channel flow introduction ch10 of hh application characteristics section parameters flow state types of flow nearys04 application pressure vs. Chapter 2 open channel hydraulics linkedin slideshare. Froude number gives an indication of the flow regime. The froude number is a ratio of inertial and gravitational forces.
The froude number, is the ratio of inertia force to gravity force, which simplifies to. In horizontal, rectangular channels, the froude number is unity at critical flow. American society assumed backwater canal channel section civil engineers cm cm cm computation crest critical depth cross section culvert curve depth of flow determined developed effect equal equation example flood flow in open flow profile flume formula friction froude number gate given gradually varied flow height horizontal hydraulic jump. Rectangular open channel flow and hydraulic design calculations, software, equations rectangular open channel design calculation rectangular open channel for river or laboratory hydraulics discharge, water depth, slope, velocity, froude. Download hydraulic engineering software hydraulic calculator 2. Inertia denominator reflects its willingness to do so. In a subcritical flow reach, the froude number is less than 1. The froude number of critical flow condition is used to calculate the critical depth in open channels 9. Froudes number applicable in open hydraulic structure. Rigimes of flow due to variation in froude number of a flow. Froehlich abstract the three basic principles of openchannelflow analysis the conserva tion of mass, energy, and momentum are derived, explained, and applied to solve problems of openchannel flow. D hydraulic depth cross sectional area of flow top width. These two types of flow are similar in many ways but differ in one important respect. Froude number, critical flow relationships in open channel hydraulics, the froude number is a very important nondimensional parameter.
More than 100 computational features provide the hydraulic engineer with a comprehensive computerized hydraulics modeling package. Before defining the hydraulic jump it is necessary to describe the terms super critical flow and sub critical flow in order to clearly understand that what is hydraulic jump hydraulic jump usually occurs in super critical flow. Even though it uses long established methodologies for open channel hydraulics, this software is new, inside and out. All channel design submittals shall include the calculated froude number fr and critical depth d c for each unique reach of channel to identify the flow state and verify compliance with these criteria. Open channel flow mcq energydepth relationship set 2 solved thefluidmechanic alternate depths, alternative depths, critical depth, critical flow, drop in bed elevation, froudes number, mcq, multiple choice questions, open channel flow, rise in bed elevation, solved mcq, specific energy, subcritical flow, supercritical flow. Check minimum permissible velocity and froude number 6. The square root of the ratio of inertia force and gravitational force is called as froude s number. An hy8 user manual is included with the software installation access via help button on top toolbar to provide important information on the technical features, capabilities, and limitations of the software. Therefore, the use of these numbers should be judged case by case. Download free excel spreadsheets for engineering calculations.
The favored hypothesis explaining erosion at the channel terminations is the occurrence of a 51 hydraulic jump i. Calculation of multiple critical depths in open channels. For instance, in open channel flow froude number is used in the scale models as gravitation. In open channel hydraulics, the froude number is a very important nondimensional parameter. Chapter seven floodplain hydraulics kean university.
Hydraulics in civil engineering bright hub engineering. Flow regime prediction via froude number calculation in a. Open channel flow mcq hydraulic jump set 1 14 mcqs. Open channel flow, a branch of hydraulics and fluid mechanics, is a type of liquid flow within a conduit with a free surface, known as a channel. Strong hydraulic jump froude number greater than 80. Summarize results with dimensioned sketch design for different lining thickness or material the base of the channel and the sides of the channel might be. Uniform flow, best hydraulic sections, energy principles, froude number assist. Hydraulic jump types and characteristics of hydraulic jump.
Presented in this book are several fortran computer programs for solving open channel flow hydraulics problems involving steady flow in irregularly shaped. Froude number dimensionless parameter to classify open channel flow the froude number is equal to 1 at critical depth gd v f classification of flow. Flow properties of horizontal rectangular channel hydraulic jumps. The other type of flow within a conduit is pipe flow.
Circular culvert software design, analysis calculation using. It is generally expressed as fr vgd12, in which d is depth of flow, g is the gravitational acceleration equal to the specific weight of the water divided by. The open channel flow calculator select channel type. A developed spreadsheet program will print out a message indicating if the. The froude number is a dimensionless parameter measuring the ratio of the inertia force on a element of fluid to the weight of the fluid element the inertial force divided by gravitational force. Its not a pretty user interface on top of government freeware. Hy8 automates culvert hydraulic computations utilizing a number of essential features that make culvert analysis and design easier. American society assumed backwater canal channel bottom channel section civil engineers computation crest critical depth cross section culvert curve depth of flow determined developed effect equal equation example flood flow in open flow profile flume friction froude number gate given gradually varied flow head loss height horizontal hydraulic. Computational hydraulics in irregular channels more hromadka. Froude number article about froude number by the free.
Channel studio is allinclusive, purpose built for open channel modeling from the groundup and needs no other software to run. Open channel flows are almost always turbulent, unaffected by surface tension, and the pressure distribution within the fluid is hydrostatic. Low cost engineering calculations software available for convection heat transfer coefficients, pipe flowfriction factor calculations, partially full pipe flow calculations, watershed time of concentration, rational method, orifice and venturi meter flow rate calculations, open channel flow measurement, activated sludge wastewater. Model studies of open channel flows and hydraulic structures are performed using a. Online hydraulic and hydrologic calculations, online. It is ratio of inertial force to gravitational force of flowing fluid. In open channel flow, the froude number is represented as the ratio of. Since the flow is uniform, the depth and discharge are related through mannings equation with sf so. The free surface is essentially an interface between two fluids of different density. By definition, an open channel is a flow conduit having a free surface. Pdf turbulence characteristics in supercritical open channel.
The froude number can be interpreted as the ratio of the inertial to gravity forces in the flow. Channel studio is allinclusive, purpose built for open channel modeling from the groundup and needs no other software. Hydraulic jump, model, visual basic, froude number, critical flow. Estimate height of lining above surface and freeboard 7. Open channel flow engineering excel templates blog. Hydraulic calculator hydrology calculations software.
348 37 817 181 1222 1071 1649 414 920 703 282 106 832 420 1445 658 1018 845 699 355 428 969 1553 426 1557 205 508 731 744 531 549 484 1119 722 250 130