# ohm's law analogy for fluid flow in a pipe

Originally Answered: What is Poiseuille's equation and how to compare it with Ohm's law? i1(t) i2(t) i4(t) i5(t) i3(t) ... Analogy: pressure drop thru pipe loop. The water pressure \(\normalsize P\) is analogous to voltage \(\normalsize V\) because it is a pressure difference between two points along the pipe that causes water to flow. R(mass) = ΔP kg s = 50 Pa 2 kg s = 25 1 m ⋅ s. Now let's multiply with the density: Water: Z(volume) = 1000 kg m3 ⋅ 25 1 m ⋅ s = 25000 kg m4 ⋅ s. Now let's calculate the flow: Waterflow (volume) = ΔP Z(volume) = 50Pa 25000 kg m4 ⋅ s = 0.002 m3 s. As we see we arrive at the right result. 13. In reality there are many limitations of such approach as operating temperatures, power … (Conservation of charge) There is a simple formula to express this relationship of pressure, flow rate, and resistance. The water is the electrical current (I) flows in the circuit, measured in amperes (A). Electric circuits analogy to water pipes. If we have a water pump that exerts pressure (voltage) to push water around a “circuit” (current) through a restriction (resistance), we can model how the three variables interrelate. Assume a disc shape element of the fluid in the middle of the cylinder that is concentric with the tube and with radius equal to r w and length equal to ∆L. I am still quite good at maths and reckon I will take higher maths as I am having tuition to up my grades. Electricity was originally understood to be a kind of fluid, and the names of certain electric quantities are derived from hydraulic equivalents. Ohm’s law is represented by a linear relationship graph between voltage (V) and current (I) in an electric circuit. Tell us what you're thinking... we care about your opinion! For more information contact us at info@libretexts.org or check out our status page at https://status.libretexts.org. The electric current and water flow can be calculated using the same Ohms Law formula: I=V/R. Also as with a resistor, the resistance to flow generated by the pipe would increase linearly with its length and decrease with its cross-sectional area, so the analogy to Equation 12.11 ( R = ρ l / A ) would be: pipe … Watch the recordings here on Youtube! It is specifically the Hagen–Poiseuille equation that is the analogy to Ohm's law. Consider a horizontal flow in a circular pipe. With current steady, voltage follows resistance (an increase in resistance means an increase in voltage). The equivalent of Ohm's law (i.e., v = i/R) would be: pressure = flow/resistance. Electrical engineer, programmer and founder of. The relationship and the unit of electrical resistance were both named for him to commemorate this contribution to physics. Show That Resistance To Laminar Flow Is Given By Deltap = 349 Pa, 14.0 GPa Which Is Independent Of Flowrate. Conductors correspond to pipes through which the fluid flows. With resistance steady, current follows voltage (an increase in voltage means an increase in current, and vice versa). Electric Current An Analogy – Water Flow in a Pipe I Coulombs/s Individual electrons are bouncing around with very high speed Electron “drift velocity may be mm/s - -----“Flow Rate” is the NET amount of water passing through a surface per unit time “Electric Current” is the NET amount of charge passing through a surface per unit time In the water circuit, the pressure P drives the water around the closed loop of pipe at a certain volume flowrate F. If the resistance to flow R is increased, then the volume flowrate decreases proportionately. [ "article:topic", "license:gnudls", "authorname:tkuphaldt", "showtoc:no", "license:gnufdl" ], Instructor (Instrumentation and Control Technology), 2.1: Ohm’s Law - How Voltage, Current, and Resistance Relate. Thus resistance to flow is given by the ratio of the pressure drop (driving potential) to volume flow rate (current). Water pressure, measured by pascals (or PSI), is the analog of voltage because establishing a water pressure difference between two points along a (horizontal) pipe causes water to flow. In relating Ohm's Law to fluid flow, the voltage difference is the pressure difference (ΔP; sometimes called driving pressure, perfusion pressure, or pressure gradient), the resistance is the resistance to flow (R) offered by the blood vessel and its interactions with … The electric current and water flow can be calculated using the same Ohms Law formula: I=V/R. The term current refers to the quantity, volume or intensity of electrical flow, as opposed to voltage, which refers to the force or "pressure" causing the current flow. Ohm's law: I = V/R : Power relationship: P = VI : Voltage Law: The net voltage change is equal to zero around any closed loop. Study specialized technical articles, electrical guides, and papers. Ohm’s Law also makes intuitive sense if you apply it to the water-and-pipe analogy. If the resistance to water flow stays the same and the pump pressure increases, the flow rate must also increase. Graphical Analysis 22 Ohm’s Law The fundamental relationship among the three important electrical quantities current, potential difference (voltage), and resistance was discovered by Georg Simon Ohm. First we'll cover co… The amount of water in the tank is defined as 1 volt and the “narrowness” (resistance to flow) of the hose is defined as 1 ohm. Ohm’s Law also makes intuitive sense if you apply it to the water-and-pipe analogy. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Ohm’s Law also makes intuitive sense if you apply it to the water-and-pipe analogy. Although this form of the equation is simply stated as voltage is equal to current times resistance, the equation’s meaning is much deeper. Ohm's Law (2.1) Kirchhoff's Laws (2.2) - Analogy: mass flow at pipe junction. With current steady, voltage follows resistance (an increase in resistance means an increase in voltage). If the pressure stays the same and the resistance increases (making it more difficult for the water to flow), then the flow rate must decrease: If the flow rate were to stay the same while the resistance to flow decreased, the required pressure from the pump would necessarily decrease: Resource: Lessons in electric circuits , Volume I – DC. Show that the resistance to laminar flow is given by R=128µL/πD^4 Continuity Equation for Flow For water flowing in a pipe under steady-state conditions (i.e., not changing over time), continuity means the water that flows into one end of a pipe must flow out of the other end. In nonideal fluid dynamics, the Hagen–Poiseuille equation, also known as the Hagen–Poiseuille law, Poiseuille law or Poiseuille equation, is a physical law that gives the pressure drop in an incompressible and Newtonian fluid in laminar flow flowing through a long cylindrical pipe of constant cross section. An analogy would be the amount of flow determined by the pressure (voltage) of the water thru the pipes leading to a faucet. When electricity is flowing there is a magnetic field surrounding it. In the water analogy, water is the medium to transfer force. \$\begingroup\$ The relationship of pressure drop, flow rate, pipe length and pipe diameter is the Hagen–Poiseuille equation. Hagen-Poiseuille equation relates the flow rate (for the laminar flow of a Newtonian fluid) of a fluid in a pipe with the pressure drop across it just the way Ohms law relates current flowing through a wire with the Potential difference across it. Let’s take a closer look. The specific conductivity {k^) 3. Fluid Flow: pipe friction, restrictions (simplified) ohms: Exceptions to the electrical fluid theory There are some cases where the gas analogy falls short too. If we have a water pump that exerts pressure (voltage) to push water around a ”circuit” (current) through a restriction (resistance), we can model how the three variables interrelate. Thanks. v1(t) v2(t) v3(t) lecture2. If we have a water pump that exerts pressure (voltage) to push water around a "circuit" (current) through a restriction (resistance), we can model how the three variables interrelate. Get access to premium HV/MV/LV technical articles, electrical engineering guides, research studies and much more! Ohm’s Law also makes intuitive sense if you apply it to the water-and-pipe analogy. Poiseuille's law 2. Parameters and concepts to describe hydraulic architecture 1. Ohm's Law also makes intuitive sense if you apply it to the water-and-pipe analogy. It is specifically the Hagen–Poiseuille equation that is the analogy to Ohm's law. The Huher value (HV) 5. This also means that the flow rate in the pipe is the same at any location along the length of the pipe. Ohm’s Law can be confusing in its usual form of I = V / R, or in other words Current = Voltage / Resistance, sometimes but it can also be stated in a different way: Current Density = Conductivity * … Question: Resistance To Fluid Flow Can Be Defined By Analogy To Ohm's Law For Electric Current. ... and current is analogous to the fluid. voltage is proportional to current is the law of ohms but here current depends upon the conductor resistance. Resistance (Resistors) In a closed circuit, resistors, measured in Ohms, are primarily used to limit the flow of current in the circuit. The battery is analogous to a pump, and current is analogous to the fluid. Learn about power engineering and HV/MV/LV substations. Thankfully for the electronics student, the mathematics of Ohm’s Law is very straightforward and simple. Ohm’s Law describes the current flow through a resistance when different electric potentials (voltage) are applied at each end of the resistance.Since we can’t see electrons, the water-pipe analogy helps us understand the electric circuits better. We have Pressure = Voltage, Resistance=Flow resistance of pipe. Laminar flow is often encountered in common hydraulic systems, such as where fluid flow is through an enclosed, rigid pipe; the fluid is incompressible, has constant viscosity, and the Reynolds number is below this lower critical threshold value. Thus, Resistance To Flow Is Given By The Ratio Of Pressure Drop (driving Potential) To Volume Flowrate (current). Imagine water flowing through a horizontal pipe. \$\begingroup\$ The relationship of pressure drop, flow rate, pipe length and pipe diameter is the Hagen–Poiseuille equation. Water flow rate, as in liters per second, is the analog of current, as in coulombs per second. ... Resistance=Flow resistance of pipe. When the electricity stops flowing, the magnetic field collapses. Missed the LibreFest? In order to understand Ohm’s law, a hydraulic analogy for beginners is sometimes useful. The amount of water in the tank is defined as 1 volt and the "narrowness" (resistance to flow) of the hose is defined as 1 ohm. An analogy for Ohm's Law Ohm's Law also makes intuitive sense if you apply it to the water-and-pipe analogy. Current = Water flow. Electrical circuits are analogous to fluid-flow systems (see Figure 4.4). The actual water flow rate F is then the analogue of current I. series multiple pipe connection. Electrical current is the counterpart of the flow rate of the fluid. The content is copyrighted to EEP and may not be reproduced on other websites. Going back to the water analogy, say this represents our tank with a wide hose. Electrical current is the counterpart of the flow rate of the fluid. Using Ohms Law, this gives us a flow (current) of … If we have a water pump that exerts pressure (voltage) to push water around a “circuit” ( current) through a restriction ( resistance ), we can model how the three variables interrelate. Current = Water flow. (This is an application of the principle of conservation of energy.) In order to understand Ohm’s law, a hydraulic analogy for beginners is sometimes useful. III. Ohm's Law also makes intuitive sense if you apply it to the water-and-pipe analogy. Conductors correspond to pipes through which the fluid flows. Review; Ohm’s Law also makes intuitive sense if you apply it to the water-and-pipe analogy. With voltage steady, changes in current and resistance are opposite (an increase in current means a decrease in resistance, and vice versa). Relative Magnitudes of Velocity Vectors: Laminar fluid flow in a circular pipe at the same direction. If we have a water pump that exerts pressure (voltage) to push water around a “circuit” (current) through a restriction (resistance), we can model how the three variables interrelate. An analogy for Ohm's Law. Current Law: The electric current in = electric current out of any junction. 87-351 Fluid Mechanics VISCOUS FLOW IN CONDUITS: MULTIPLE PIPES [ introduction ] As we have discussed before, an interesting analogy exists between fluid and electrical circuits. We see in Ohms law, that voltage, e, is a product of the electric current, i, and the conducting resistance, R -  Basically, for a given pressure drop, flow rate is proportional to the 4th power of pipe diameter. If we have a water pump that exerts pressure (voltage) to push water around a "circuit" (current) through a restriction (resistance), we can model how the three variables interrelate. The resistance of a pipe to fluid flow can be defined by analogy to Ohm's law for electric current. ohm’s law states that at constant resistance voltage is directly proportional to current .you missed the resistance yaar. If the resistance to water flow stays the same and the pump pressure increases, the flow rate must also increase. The elec­tronic–hy­draulic analogy (de­ri­sively re­ferred to as the drain-pipe theory by Oliver Lodge) is the most widely used anal­ogy for "elec­tron fluid" in a metal con­duc­tor. Student Section – Water Analogy to Electric Circuits Flow rate (Current) in a Series Circuit The flow rate (current) of water through the circuit can be detected with the flow meter (ammeter), which turns faster for a higher flow rate and slower for a lower flow rate. In reality there are many limitations of such approach as operating temperatures, power dissipation and power limits. Unless otherwise noted, LibreTexts content is licensed by CC BY-NC-SA 3.0. If we have a water pump that exerts pressure (voltage) to push water around a ” circuit ” (current) through a restriction ( resistance ), we can model how the three variables interrelate. There is a simple formula to express this relationship of pressure, flow rate, and resistance. Thus resistance to flow is given by the ratio of the pressure drop (driving potential) to volume flow rate (current). A hydraulic analogy. Have questions or comments? Fluid-Flow Analogy . ... (volts) in the pipe, the gallons per minute of water flow (amps), and the restrictive effect of the pipe and valve diameter (ohms). Basically, for a given pressure drop, flow rate is proportional to the 4th power of pipe diameter. If we have a water pump that exerts pressure (voltage) to push water around a "circuit" (current) through a restriction (resistance), we can model how the three variables interrelate. The unit pipe mode! The battery is analogous to a pump, and current is analogous to the fluid. Using this analogy, let's now look at the tank with the narrow hose. Imagine water flowing through a horizontal pipe. 4. ... (volts) in the pipe, the gallons per minute of water flow (amps), and the restrictive effect of the pipe and valve diameter (ohms). You may click any component or any relationship to explore the the details of the analogy with a DC electric circuit. We can imagine the Ohm’s law using the water pipe illustration: The water pipe is the resistance (R) in the circuit, measured in ohms (Ω). A common technique to solidify understanding is to learn the hydraulics analogy of electricity, which is arguably easier to visualize than electricity itself. Water storage capacitance (Q) 6. Legal. With resistance steady, current follows voltage (an increase in voltage means an increase in current, and vice versa). I might be able to (fingers crossed) convince my school to let me take electronics, hopefully it will work. Electrical circuits are analogous to fluid-flow systems (see Figure 4.4). Ohm's law analogy II. A hydraulic analogy is sometimes used to describe Ohm's law. The water pressure P is analogous to voltage V because it is a pressure difference between two points along the pipe that causes water to flow. If the resistance to water flow stays the same and the pump pressure increases, the flow rate must also increase. I’m currently doing electronics and have to say about Ohm’s law for homework. If the resistance to water flow stays the same and the pump pressure increases, the flow rate must also … Since electric current is invisible and the processes in play in electronics are often difficult to demonstrate, the various electronic components are represented by hydraulic equivalents. Show that the resistance to laminar flow is given by R=128µL/πD^4 Water flow through pipes and the unit pipe model 1. Thanks for the info though, one of the most simple and clear explanations I have seen yet. An analogy for Ohm’s Law. Ohm's Law also makes intuitive sense if you apply it to the water-and-pipe analogy. If the pressure stays the same and the resistance increases (making it more difficult for the water to flow), then the flow rate must decrease: If the flow rate were to stay the same while the resistance to flow decreased, the required pressure from the pump would necessarily decrease: As odd as it may seem, the actual mathematical relationship between pressure, flow, and resistance is actually more complex for fluids like water than it is for electrons. The LibreTexts libraries are Powered by MindTouch® and are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. If the resistance to water flow stays the same and the pump pressure increases, the flow rate must also increase. If you pursue further studies in physics, you will discover this for yourself. Ohm’s Law also makes intuitive sense if you apply it to the water-and-pipe analogy. With voltage steady, changes in current and resistance are opposite (an increase in current means a decrease in resistance, and vice versa). That said, fluid flow can be used as a decent analogy for certain things. Using Ohms Law, this gives us a flow (current) of 1 amp. The hydraulic conductivity {k^) 2. If we have a water pump that exerts pressure (voltage) to push water around a "circuit" (current) through a restriction (resistance), we can model how the three variables interrelate. The leaf specific conductivity (LSC) 4. Circuit set-up Find the following items: o two straight connectors Ohm’s Law is defined as \(V = IR\). If we have a water pump that exerts pressure (voltage) to push water around a “circuit” (current) through a restriction (resistance), we can model how the three variables interrelate. I really want to take electronics for GCSE, but you have to be in level 7/8 maths sets :(. The electronic–hydraulic analogy is the most widely used analogy for "electron fluid" in a metal conductor. This is easily visualized in the picture above as we see the resistor squeezing the pipe that allows the current to flow … Water Pipe Analogy for Ohm’s Law. The resistance of a pipe to fluid flow can be defined by analogy to Ohm's law for electric current. It's not uncommon for someone (even those who take degrees with significant coverage of electricity and magnetism, such as physics and electrical engineering) to struggle with understanding how both a circuit as a whole and its individual components function. If the resistance to water flow stays the same and the pump pressure increases, the flow rate must also increase. It helps you. Let's say this represents our tank with a wide hose. In the water analogy, water is the medium to transfer force. 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With resistance steady, voltage follows resistance ( an increase in current, and the of... Is flowing there is a simple formula to express this relationship of pressure, flow rate ohm's law analogy for fluid flow in a pipe! Doing electronics and have to be in level 7/8 maths sets: ( Law is very straightforward and simple pressure!