What is Hydraulic: Definition and 338 Discussions

Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counterpart of pneumatics, which concerns gases. Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the applied engineering using the properties of fluids. In its fluid power applications, hydraulics is used for the generation, control, and transmission of power by the use of pressurized liquids. Hydraulic topics range through some parts of science and most of engineering modules, and cover concepts such as pipe flow, dam design, fluidics and fluid control circuitry. The principles of hydraulics are in use naturally in the human body within the vascular system and erectile tissue.
Free surface hydraulics is the branch of hydraulics dealing with free surface flow, such as occurring in rivers, canals, lakes, estuaries and seas. Its sub-field open-channel flow studies the flow in open channels.
The word "hydraulics" originates from the Greek word ὑδραυλικός (hydraulikos) which in turn originates from ὕδωρ (hydor, Greek for water) and αὐλός (aulos, meaning pipe).

View More On Wikipedia.org
Recent contents Top users
  1. H

    Automotive How to calculate hydraulic disc brake size using actuation force?

    hello, How do i calculate brake size using force of actuation? im designing a hydraulic disc braking system (only one rotor caliper located in the middle of drive shaft) for go kart and using simple pascal law, i have calculated the force of actuation of the hydraulic brake that is the force...
  2. S

    Building a Hydraulic Robot Arm: Overcoming Syringe Length Limitations

    I have to make a hydraulic robot arm that can lift a cup of water up and down 8 inches, pour it and move it left and right 8 inches. Only problem is the assorted syringes we are required to use has a length of at most 6ish inches. How do I make it push farther and lift higher. BTW I can only use...
  3. Hans Heyde

    Calculate hydraulic motor for a Flywheel

    Gentlemen: I got stuck in this problem and I really need your help: I have an hydraulic line of 23Mpa ( 3.300 psi) 10 gallon/min I built a flywheel weight 58,000 grams with the following Inertial properties Principal moments I1= 2.5 , and I2= 2.3 and I3= 632170437 grams mm3 Flywheel will...
  4. L

    Changing hydraulic pump cartridge can give me more torque?

    hi all, changing my cartridge of 21 gpm to a small one 12 gpm I will have more torque whith less rotation in my winch hd motor? it's sound correct? if yes have a formula to know how much more % ? obs - keeping same pressure and same engine HP drive rpm . in case of will need more...
  5. A

    How Do Hydraulic Systems Apply Pascal's Law?

    Homework Statement The large cylinder in a hydraulic press has 3 times the surface area of the small cylinder. What force should be applied to the small cylinder to create a lifting force of 7200 Newtons In a hydraulic-brake system, a force of 25 N can be applied to a surface area of 5 cm^2...
  6. jack action

    Sizing hydraulic (brake) lines

    On older GM cars, the brake lines are 3/16" from the front port of the master cylinder, splitting into two 3/16" for each front wheel, and 1/4" from the rear port of the master cylinder, splitting into two 3/16" for each rear wheel. This is the case for drum/drum or disc/drum configurations...
  7. R

    I Size of links and loads in the hydraulic system

    I am currently in the process of creating my own design in which every millimeter counts. I have the following question: does the cross-section area of the highlighted link make a difference, and does decreasing the area makes force exerted on the walls greater? My guess is that cross-section...
  8. P

    Volume Flux for a Hydraulic Jump

    Homework Statement Problem is given in this image, https://gyazo.com/454370ff9549dcd7c53604ebfe5df105 Homework Equations Continuity or conservation of mass equation: \frac{\partial u}{\partial x} + \frac{\partial w}{\partial z} = 0 Where u is the horizontal velocity and w is the vertical...
  9. bdolle

    B How can I derive the hydraulic equation using conservation of energy and work?

    Hey All, Question about hydraulics. Can't seem to find anyone videos or material to walk me through how to get the formula deltaF = rho*g*(A1+A2)d2 Any takers? My book states: The conclusion is conservation of evergy. Work is done on the liquid by a small force pushing the liquid through a...
  10. fando1234

    Lifting an elephant with hydraulics

    Hey guys, I'm a super amateur at physics, but I occasionally like to calculate random problems that pop into my head. Today I was thinking about pascal and hydraulics, and wondered if I could devise a (hypothetical) hydraulic system that would allow my weight to lift an elephant. I want to...
  11. L

    Can a 2500 Gallon Water Tank Sufficiently Cool a Condenser Without a Chiller?

    Hello! Hopefully someone here can help with this problem: I have a condenser that holds 35 gallons of water to cool the copper coil on my still. I need to know if I can create a closed loop system of cooling water that allows me to avoid running a chiller. I know that there is probably an...
  12. T

    Can hydraulic systems replace ebikes in power assisted cycle

    Instead of an electric motor, can it be substituted with an hydraulic force / power amplifying system instead? If yes, how would it work? Could chains still be used? Instead of an electric motor powering the hydraulic system, could the rider power the hydraulic system through force / power...
  13. N

    Annulus force in a Hydraulic Cylinder?

    Hi, I was wondering if I could ask for some advice. I'm was calculating the Annulus force that a hydraulic cylinder could generate that I've been asked to do some work on, however this particular ram is a little unusual in that it had a split rear piston and necks down to a smaller diameter than...
  14. K

    Hydraulic piston force as a function of angle for a launcher

    Hello, A friend of mine challenged me with a question related to erection of missile launcher. For some reason and after too long struggling with it i gave up and trying now to figure out what is the point that I'm missing. The task is to fine the force that the piston is "feeling" as function...
  15. B

    Hydraulic Press actual Press Force (tons)

    Hi all. I am new to this site and I would like to verify the following calculation. Is it correct to do it this way? Please advise. Thanks. Hydraulic Press: 15 tons (Enerpac RC1510) Gauge Max Pressure: 10000 psi Actual Gauge Reading: 2500 psi Actual pressure (tons) = (2500/10000) X 15 tons =...
  16. S

    How does a hydraulic machine work?

    Homework Statement How does a hydraulic machine work? Homework Equations P=F/A The Attempt at a Solution I know that these work because the pressure is the same throughput the system and that these are multiplier machines because the force is magnified by the magnified area, but I don't...
  17. M

    Bernoulli's equation, Venturi effect, hydraulic head, nozzle

    Hi, I have this problem: I have a vertical tube 1 meter D, in the bottom end there is a nozzle with 0,5 m D. The tube is full of water. the tube length is 10 meters and the nozzle length is 2 meters. I need to calculate the power of this by this equation: W = Q * g * h * p where W is watt, Q...
  18. F

    Flow thru a channel constriction

    Homework Statement When a part of the channel is constricted , why will the Emin = Eo ? Homework EquationsThe Attempt at a Solution I just have the figure showing in case 1 and case 2, Emin = Eo without any explanation ... Can someone explain about it ? I tried to search many online resource ...
  19. T

    Pressure drops in hydraulic dampers

    Homework Statement Hi there, I am having a theoretical dillema which does not involve a specific problem, rather I am thinking of this scenario in my head and I am not sure how to go about it. I am unsure whether to calculate P2 using the head loss or using the bernoulli equation. Because in...
  20. F

    Hydraulic conductivity in soil

    Homework Statement why there's no horizontal conductivity in this question ? Homework EquationsThe Attempt at a Solution IMO , there's also horizontal conducitivity in this question because of the water can also flow horizontally across layer A , B and also C . [/B]
  21. C

    I What is the significance of bandwidth in hydraulic transmission lines?

    Hello, I am reading a book about simulation, modeling and automatic control. In a chapter about hydraulic transmission line, a pipe's "bandwidth" is mentioned. Contex: "Long pipes are used in large hydraulic installations where pipes of length up to 10 m are not uncommon. Moreover, in offshore...
  22. F

    Understanding Hydraulic Jump: Basics & Calcs

    Homework Statement http://www.brighthubengineering.com/hydraulics-civil-engineering/55054-open-channel-flow-basics-hydraulic-jump-calculations/ In th earlier part of this notes , i was told that the The hydraulic jump is an abrupt transition to subcritical from supercritical flow. but , in...
  23. F

    Calculating Best Hydraulic Section for Composite Channel - Flow Rate 6.5(m^3/s)

    Homework Statement Determine the depth of the flow of channel if the best hydraulic channel is needd for composite channel in figure to convey flow rate of 6.5(m^3/s) , Manning coefficient n on bed slope are 0.015 and 0.0015 respectively . Homework EquationsThe Attempt at a Solution I assume...
  24. T

    Is the Bernoulli Equation enough to determine pump selection?

    Here is an illustration of something that came into my head: http://imgur.com/a/V9V8S (also attached to question) If we do a energy balance (in terms of head) between point 1 and point 2 (ignoring friction for now, it's not really important): $$\frac{P_1}{\rho g} + \frac{v^2_1}{2g} + z_1 +...
  25. Mechanic7

    Hydraulic system - Design optimization

    Homework Statement Hello all, I'm a Mechanical engineer with no prior experience in designing flow systems. I'm struggling with a hydraulic system that I have to design. the number of unknowns is large. but maybe by dividing the system to small sections, a solution can be found. I attached...
  26. Vardges

    Hydraulic motor-AC generator coupling

    Hi there. I have an idea which is interesting. Let's suppose, we have AC generator which has capability of 100 KW and 100 RPM. And we have hydraulic motor which produces 500 RPM and 2400 Nm torque. Additionally, I attach 5:1 gearbox for reducing 500 RPM to 100 RPM for Ac generator. Please, share...
  27. M

    How to Solve Hydraulic Jump Problems with Conservation of Momentum and Mass?

    Homework Statement The question is stated here, though I'm happy to repost but they include a picture. I should say this is not homework, I'm doing problems for practice. http://web.mit.edu/2.25/www/5_pdf/5_04.pdf Homework Equations Conservation of momentum/mass The Attempt at a Solution...
  28. W

    I Variable displacement hydraulic pumps

    In online examples of variable displacement systems with swash-plate pumps, the input pump & motor are usually of equal size. When the constant RPM input pump is at full tilt (max displacement) the fixed displacement motor is at the same RPM for a 1:1 ratio, and when the pump is at no tilt (no...
  29. adska

    Hydraulic Engine: Ball Spin, Stop & Why?

    What will happen with metal ball in the below picture? it will spin? if yes, when it will stop and why? I am not very faimiliar with physics, but I am sure that ball must spin :D http://www.cagof.com/Untitled.png
  30. R

    I Calculating FvD for Hydraulic Cylinder with Air Bubble

    I want to calculate the force-displacement curve for a damper that would have hydraulic oil with an air bubble in it, so very similar to an air spring with a limited amount of volume. I came up with the following solution: F(x)=Po*A((Vo/Vo-A*x)-1) where F would be the external force applied...
  31. S

    Hydraulic system used in cnc machines

    I have found some uses of hydraulic systems in cnc machines in http://www.trendingtop5.com/hydraulic-system-used-in-cnc-machine/ . But those are not enough for me. please suggest some another uses in the modern industry.
  32. K

    How can a hydraulic cushion valve prevent jerking loads on a gillnet reel?

    I have a commercial fishing boat with a gillnet reel,basically a large winch. The reel is powered by a hydraulic motor and a chain drive/sprocket setup. It uses a reversing hydraulic valve with load checks,I think they are called. When the motor is activated/deactivated it comes to a complete...
  33. A

    Topic: Hydraulic Fluids in Aviation

    Hello, We all know that, in Commercial aviation, we use Hyjet (SKydrol or 500B4). and in military we use MIL-H-83282 (red oil). what are the main reasons? MIL-H-83282 has a synthetic hydro carbon base and contains additives to provide the required viscosity and anti wear characteristics, which...
  34. M

    A Attenuation and Packing in hydraulic Transients

    Hi 1- How can justify two phenomenon 'Attenuation' and 'Packing' in fluid transients in pipelines? Is it possible to explain and account for those with Newton's third law? 2- Regarding to what Chaudhry says in his book ('Applied Hydraulic Transients', P. 192 of 1979 edition, Chapter 7, Part...
  35. putta

    How to fix pressure transducer to Hydraulic line

    Dear Experts, I want to put new feature for my hydraulic pressing station (capacity:-350TON). present it existing with dial type pressure indicators. and directional propositional valve 3/4 for pressure lines. here value are made DAIKIN (JSO-G03-2CB-10) this model top side Alean key thread...
  36. H

    Hydraulic Motor & Constant Torque

    Hi, I'm a beginner on hydraulics and have been reading up a lot of literature. But I'm not sure if my assumptions are accurate and I hope I can discuss with other forumers here! My apologies in advance if my questions seem silly! Background: My goal is to drive a hydraulic motor at constant...
  37. T

    Automatic hydraulic jack -- choosing motor

    What type of motor can I use for this jack ? It's running from a 12V battery
  38. O

    Electrical position feedback for hydraulic servomechanism

    Homework Statement Assume that you are employed by a company that manufactures hydraulic servomechanisms. You have been asked to recommend an electrical method of providing position feedback rather than the mechanical method used at present (pictured below). The demand signal has been chosen...
  39. cjpa

    A Understanding Force Diagrams for Hydraulic Cylinder Selection

    Hello world, I have to select an hydraulic cylinder to counter-balance a force. For that purpose I need to know the force that my hydraulic cylinder must exert. Typically I would use the horizontal part of F2, but being that force with diferent degrees, doen't my friction play an important...
  40. F

    Hydraulic grade line (HGL) vs energy line (EL)

    Homework Statement i was told that the major loss causes EL and HGl to decrease gradually , while minor loss causes EL and HGL to decreses rapidly ... Why ? Homework EquationsThe Attempt at a Solution is it because the minor loss(energy loss-( which is caused by the friction loss in the bent...
  41. F

    Hydraulic Diameter Explained: 4.4 vs 4.5

    Homework Statement why in 4.4 the author gave D =4Rh? in 4.5, D= 2Rh ? Homework EquationsThe Attempt at a Solution
  42. H

    Hydraulic diameter vs hydraulic radius

    Homework Statement i was told that the hydraulic diameter = 4Ac / p , while the hydraulic radius = Ac / p , where Ac = cross sectional area , and p = wetted perimeter of the pipe , why shouldn't the hydraulic radius = 2Ac / p ? because as well all know , diameter = 2 Radius , so hydraulic...
  43. K

    Hydraulic Circuit Controls?

    I don't know if this is the place to ask this, but I am a mechanical engineering student about to finish a degree, and I have recently been researching hydraulics. After watching a rear loading garbage truck eat bag after bag going down my street, I can't help but wonder a few things. I...
  44. Turbine

    Optimizing Pin Diameter and Column Thickness for Hydraulic Press Design

    Hi guys, Working on a 50-ton hydraulic press design using a standard H-frame design, like this: I'm working on the design of the vertical members. Similar to the photo above, the verticals have 1.25" diameter holes drilled for pins that support the horizontal bed. The problem: while...
  45. I

    Basic hydraulic pump work-energy relationship

    I have a very simple question that's been driving me nuts. It's biology context, but probably all the physics equates to normal positive displacement pumps. The pressure in and volume of the left ventricle of the heart can be measured experimentally. (For example...
  46. T

    Use of draft tube in Francis turbine to increase output

    Work output(deal) for a hydraulic machine per kg of incoming fluid is V(TANGENTIAL)*SPEED OF BLADE (assuming zero out swirl velocity. Draft tube causes static pressure ont runner outlet to fall below zero. Thus available head is increased by an amount equal to this drop. But power output from...
  47. E

    Passive Hydraulic System to Transmit Mechanical Power

    Hi All, I am trying to displace mechanical power using a hydraulic system with the fluid as the energy conduit. I will be using two cylinders with a connecting pipe, so when I push one down the other rises. This video illustrates well what I am going for in terms of hydraulic topology. My...
  48. A

    What is the conversion factor for hydraulic conductivity units?

    Hi I am new to the forum, I am using darcy's equation to model a tumor - tissue medium. In the literature I found that K - Hydraulic conductivity is given by cm^2/(mmHg.s) But in comsol it's given by (m/s) Is there another term involved in this?
  49. J

    Horizontal open channel flow -- Hydraulic jump calculation

    Dear Fellow Engineers I'm having an issues with my calculations. This case concerns a open channel flow that start off being supercritical on the left and turns into subcritical flow after a hydraulic jump. Given: Volume flow rate Q = 0.16m^3/s Width of the channel b = 1m Resulting...
  50. T

    Basic Hydraulic Power System Diagram for Fan Movement

    http://postimg.org/image/pdm3b1e1v/ Please take a look at this basic hydraulic fan picture Can anybody make a simple hydraulic power system diagram to keep the fan moving. Please list down the parts and arrow indicating how it works. Can anybody do it? hmmmm...
Back
Top