What is Water flow: Definition and 161 Discussions

Environmental flows describe the quantity, timing, and quality of water flows required to sustain freshwater and estuarine ecosystems and the human livelihoods and well being that depend on these ecosystems. In the Indian context river flows required for cultural and spiritual needs assumes significance. Through implementation of environmental flows, water managers strive to achieve a flow regime, or pattern, that provides for human uses and maintains the essential processes required to support healthy river ecosystems. Environmental flows do not necessarily require restoring the natural, pristine flow patterns that would occur absent human development, use, and diversion but, instead, are intended to produce a broader set of values and benefits from rivers than from management focused strictly on water supply, energy, recreation, or flood control.
Rivers are parts of integrated systems that include floodplains and riparian corridors. Collectively these systems provide a large suite of benefits. However, the world's rivers are increasingly being altered through the construction of dams, diversions, and levees. More than half of the world's large rivers are dammed, a figure that continues to increase. Almost 1,000 dams are planned or under construction in South America and 50 new dams are planned on China's Yangtze River alone. Dams and other river structures change the downstream flow patterns and consequently affect water quality, temperature, sediment movement and deposition, fish and wildlife, and the livelihoods of people who depend on healthy river ecosystems. Environmental flows seek to maintain these river functions while at the same time providing for traditional offstream benefits.

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  1. A

    Water Drain Channel minimal cross-section

    Hi there! I'm looking for an approx. minimal size for a drain channel where condensation water can go through. Can anyone have some advice? No increased pressure for the water, just the normal atmospheric pressure. Water condensing and just have to be able to get out. The amount of water is...
  2. CarlPace

    Misc. DIY RC Boat with Parallel Impeller

    I'm not sure if you would call it a "Parallel Impeller," but the pics below should tell the story. I'm designing/3D printing my next RC boat from scratch, and I wanted to try something different from tried-and-true propeller and shaft system. Reasons? 1. Fun. 2. Using a "wet" brushless motor...
  3. dadthedestroyer

    increasing pipe size and then decreasing

    Seen a lot of videos of a guy increasing and decreasing the pipe size on YouTube and changing the flow of water or the pressure. It seems an explanation of how this works would be nice. I understand a little bit about flowing pressure. Is there any other things that involved in this?
  4. A

    Engineering Water Flow from Pressurized Tank through Heat Exchanger

    Hi All- New member here. As the title states I am trying to solve the flow volume of water from a pressurized storage tank through a heat exchanger and then discharging out the end of a pipe. I have been working on this for several days now without any luck, seems like now I am just throwing...
  5. SpaceDuck127

    Derivation of a Simplified D'Arcy's Law Equation

    By substituting the darcy-weisbach equation into darcy’s law we get q = -kf/µL * (L/D) * (𝜌V^2/2) This can be further simplified by substituting the equation for friction factor for laminar flow, f = 64/Re , with the equation for reynolds number, Re = ρVD/µ substituted in such that: q =...
  6. gamecult

    Bernoulli equation for calculation of water flow

    Hello everyone; Please need some help to check if my calculation are correct (and if possible some explantation) Bernoulli's equation between point 1 and 3 is given by: P_1+1/2 ρv_1^2 + ρgh_1 = P_3+1/2 ρv_3^2 + ρgh_3 P_1 = P_(atm ) v_1= 0 m/s h_1= 0.875 m P_3 = P_(atm ) v_3= ? m/s h_3= 0...
  7. C

    Poiseuille equation for water flow rate

    For this problem, The mains water pressure at the council tubby (just before it enters a house) is of the order of 1.5 bar. Using Poiseuille equation, estimate the flow rate in a typical home at the kitchen tap. You will need to make reasonable estimates on several parameters, clearly state...
  8. J

    Water flow thru 18" corrugated culvert

    Attached formula can't figure out. H is 12 inches, Q is what I want to know, L is 40 feet, D is 18 inches, A I assume is area of 18 inches, g have no clue what this is. The Culver is 18" X 40 foot long coragated with water 1 foot over inlet and water on outlet 2" lower than culvert and the...
  9. RawPotatoes

    I Issue calculating water pressure due to the constriction of water flow

    For an experiment where I must be able to control the pressure i attached to a syringe a 'chamber'. The inner diameter of the syringe is 19.3 mm and i will fill water to 17 cm of the syringe bottom (i call this P1), the spout has a inner diameter of 2 mm and a length of 2 mm (i call this P2) and...
  10. richengle

    How does water flow from a faucet?

    water flow from a faucet will neck down its radius as it flows to the bottom of the sink. It is asserted that this is due to the fact that gravity increases the velocity of the fluid. This is shown at . I am trying to simulate this, and am not having much luck. shows this for a flat...
  11. F

    Water flow rate and drip surface tension

    hello i have a drip tube with water dripping and when i increase the flow rate or frequency of drips they get bigger/more massive. i see the equation mass x gravity = 3.14(tube diameter)(surface tension) my mass is changing but not gravity, 3.14 or tube diameter so surface tension must be...
  12. jahinparvez

    Water flow through a reducer

    When water flows from a large diameter to small diameter through a reducer, i know pressure will decrease from bernoulli eq. But what happens (increase or decrease) to the other various thermodynamic properties such temperature, enthalpy, internal energy, entropy, and specific volume?
  13. P

    Water flow through a packed bed

    Suppose you have a cylindrical column filled with packed, irregularly shaped particles. The bottom of the cylinder is flat and closed except for an array of small circular holes, regularly spaced except for a ring around the edge of the bottom where there are no holes. So, holes everywhere on...
  14. EEristavi

    Torque generated by water flow

    I know that I have to calculate force that is generated by water. However, I do it wrong way. ## A = \pi r^2 ## ## v = \frac Q A = \frac Q {\pi r^2}## ## F = P t = mvt = ...? ## - have problem with mass. and is it even correct way? if I can calculate F - its easy afterwards... ##\tau = F l ##...
  15. BillTre

    I Is Late Water Flow on Mars Linked to Climate Change or Permafrost Melting?

    Perhaps this thread would be better located in the Earth forum (where hydrologists might more likely see it), but it is Mars not Earth. I recently read about a study on riverbeds (size, catchment size, meandering) on Mars that claimed large water flows in some riverbeds "late" in Mars history...
  16. Roy S Ramirez

    How can I predict the flow rate for a real life water hose?

    Hello! I hope you are all doing well! I've been always intrigued by fluid mechanics and decided to try out a quick experiment with my water faucet. After using some equations I found online [1] [2], I plugged a hose to the faucet and let the water run. I filled a 1 quart bowl and recorded the...
  17. Gabriele99

    Will water flow ever stop if we increase resistance?

    Complete question: Will flow ever reverse or stop if we increase resistance in this pipe scenario? There are 2 comunicating vessels. The highest vessel is coninuosly alimented with new water. Water in excess flows down on the sides. Water will try to reach the same height in both vessels, so...
  18. K

    Calculating Velocity of Water Flow in Open Channel

    Homework Statement [/B] We have water flowing in an open channel. A small tube is placed in the channel, and the water raises to a height "l" above the water surface. The distance from the water surface to point 1/2 (points are at same height) is d. At point 1 the fluid velocity is V1 and at...
  19. Moayd Shagaf

    Equation for Water Flow Over Pipe Circular Hole

    suppose a water falling from pipe that above the ground with 5 meters, what is the equation that describe the level of water ( h) from pipe the hole at every moment of time? consider the pipe hole is circle .
  20. S

    Rate of water flow into an immersed container

    Hi, I am wondering how I may calculate the rate of water flow into a container(say, a empty box) with a hole in it, and with the whole box immersed in water. Does it have something to do with the force of water pushing against the container, and calculating how fast water can flow through the...
  21. Anachronist

    Water flow from pressurized tank - versus temperature

    Bernoulli's equation gives us this as the flow rate from a pressurized tank: $$v = C_v \sqrt{2gh + \frac{p}{\rho}}$$ where ##C_v## is the velocity coefficient, ##g## is the acceleration due to gravity, ##h## is the height of the water above the exit hole, ##p## is the excess pressure above...
  22. Mechanic7

    Water flow system - Design an Optimization

    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 a schematic drawing...
  23. A

    Calculation of water flow rate in heat exchanger

    I am not a mechanical engineer; but I have physics background. I want to lift about 250 watts of heat from a metal block. At the same time I have to maintain its temperature at 30 deg Cel. For this I want to use water-air heat exchanger (HE). Heat exchanger will have inlet & outlet pipes. Hot...
  24. C

    Water Flow Mechanics: Solving a Homework Statement

    Homework Statement The Attempt at a Solution I do not understand why it tells me to compute the min. flow rate instead of max. and I don't whether I am correct[/B]
  25. J

    Diameter of hole vs time to submerge

    Hey everyone, I'm new to physics forums and I would really like some help with my physics report. For my high school physics topic I have chosen an experiment where holes with differing diameters are drilled into the centre of the bottom of PVC pipe caps and the time taken for the each cap to...
  26. G

    Water spray from a pipe hole

    Homework Statement How far will water shoot from a hole in a pipe knowing the pipe pressure, hole size, and exit liquid velocity and flow rate. It is assumed that the hole is located such that the water is sprayed at a 45 deg angle from the horizontal. Homework Equations Basic projectile...
  27. Ravi Singh choudhary

    How to lift water up to 5 metres without using a pump?

    I was asked how you can lift the water up to 5 meter but you are not allowed to use any kind of pump. What I thought; seal the container from where water is being lifted. Connect it with a pressure vessel at some height which is containing steam and water with valve in between them. By default...
  28. K

    Maintaining a constant volume of water in a tank

    I have water draining from a tank A into a tank B through a hole (or short pipe) and then being pumped back from B to A. If I know the rate of the pump (say 19 liters per minute), what should the diameter of the hole be so that the volume of tank A remains the same? The actual volume of A is...
  29. J

    Make water flow up in pipe

    Good day to you all, some of you may be able to help me with my problem. So I have a flat roof and I have a pipe that goes from the roof to the ground and it drains all the water. I want to extend the pipe to a rain barrel, so I can use it for the garden. The rain barrel has an opening at the...
  30. T

    B How Tube Size & Openings Impact Water Flow

    What affects how fast the water come out of the tube?(size of tube, size of opening where the water enters, etc) thanks in advance.
  31. F

    Resultant force at elbow from water flow

    Homework Statement water flows in an elbow was aligned horizontally , of angle 135 degree . If the water volume is section 1 and 2 is 0.2m^3 , the elbow is 12kg , flow rate is 0.4(m^3)/s , find the resultant force Homework EquationsThe Attempt at a Solution i found x and y component of the...
  32. F

    Explaining Water Flow: Inlet vs Outlet Pressure

    Homework Statement this is a pipe where the water flow from low to high. assuming no friction loss (volume rate are constant at both inlet and outlet) , is the pressure at inlet = pressure at outlet ? p/s : inlet and inlet diameter are same Homework EquationsThe Attempt at a Solution my...
  33. O

    How is Bernoulli's equation related to saxon bowls?

    Homework Statement This is a lab that we have to design and carry out that goes above and beyond our course. I am investigating how the diameter of a hole in a bowl affects its sink time when put in a larger bowl of water (saxon bowl, or sinking bowl as they are known.) I will have to plot them...
  34. M

    Rate of water flow experiment question

    Hi, I am mike from australia, I am new to the forums and am having trouble answering the question below, I have included some information on the experiment as well. You are given a water bottle with a pin sized hole in the bottom, and a line drawn around the bottle at the level that 50cm3 of...
  35. L

    How does opening multiple valves affect the water flow through pipes?

    Homework Statement I'm going to regulate a tank using a PID-controller. I want to simulate this in MATLAB though and met a problem while calculating the mathematical model. The problem is the following: The three valves are either fully open or fully closed. The diameter in the pipes are all...
  36. F

    Energy Flow from Low to High: Exploring the Water Flow

    Homework Statement As we all know , energy will lose from high to low. in the equation , the energy at A ( Pa +za +](Va)^2 ]/2g ) is higher , while the energy at B is lower. So, why the water flow from B to A ? why not A to B ? 20.39 +10.52-hf = 32.98 Homework EquationsThe Attempt at a Solution
  37. C

    Water flow through a perforated plate

    Hi, I'm seeking the formula to calculate how water moves from one tank into another through a perforated plate driven by waterlevel compensation. I found the calculation for the discharge of water through submerged orifices, but I think the calculation does not include that holes, one above the...
  38. Neeps

    Sailboat rudder physics, and water flow estimate

    Hi. I'm a computer science student developing a kalman filter for autonomous sailboat, but I severely lack knowledge of the physics behind sailboats. I have a wind sensor giving data about wind speed and wind velocity, problem is the data is unreliable. So i thought that i could estimate what...
  39. I

    Efficient water heating system

    I want to design a water heating system for a special type of pool. The system is open-loop, where input water at 10 C has to be heated to 15 C, and then enters the pool and is eventually exhausted out of the pool. The flow rate is about 100 litres/second (6000 litres/minute). Simply heating up...
  40. Shadow-Shocker

    Electrical Build DIY Mini Water Pump: Solve Problems Now

    I am building a mini water pump out of a 3L plastic container, a 6V mini motor, 12 inch straws, a cut up CD for a cover (in the pic it is what is between the fan and straw), and bits of a soda can to make up a fan for the motor. Problem is when I tested the product, not enough water/air is...
  41. M

    Can Recycled Water Flow Uphill in a Pressure System?

    Hi In this system of water flow, water enters pipe A at x pressure with the aim of pumping it to the house Excess water or rather recycled water is flowing back via pipe B into pipe A Is that possible according to the law of physics i.e. will the pressurised water attempt to flow up into pipe B...
  42. T

    Water Flow Through a Pipe w/180° Horizontal Elbow

    Homework Statement Water flows through a circular pipe with a 180° horizontal elbow and exits to the atmosphere through a nozzle as shown in Fig. Q3. The diameter of the pipe is 300 mm and the diameter of the nozzle exit is 160 mm. The density of water is 999 kg/m3 . The mass flow rate of...
  43. T

    Relationship between water flow and pressure drop

    A building has a water pipe inlet. I have found that at if I open the valve at this location fully, then I get 180 liters per minute at a residual pressure of 0,2 bars (static pressure is 5,4 bars). Is there a fixed relationship between the flow and pressure drop so that I can easily predict...
  44. U

    Water flow out of a cylinder?

    Homework Statement Ok, so the height of the cylinder is 5.5 meters. The radius is 1 meters. There is a hole, .5 meters from the bottom(5 meters from the top), its radius is .02 meters. The question is how fast does water flow out, relative to time(this because the height of the water keeps...
  45. James O'Neill

    How to calculate acceleration in a funnel

    I have seen some tidal turbines that have funnel ducts around them to improve efficiency. So how would one calculate water acceleration in a funnel? If you want figures: water velocity - 3 m/s funnel opening A (largest) - 8 meters funnel opening B (narrowest) - 5 meters Distance between A and...
  46. Pumpquestions

    Will this pump work for my artificial irrigation system?

    Hi all, I am designing an artificial rain system and was thinking about using http://www.dannermfg.com/Store/Products/Danner/PID-02720.aspx to power it. The goal of the system is to deliver roughly 1 gallon of water per hour to each of the 8 exit points (I will measure this by using a bucket...
  47. R

    Venturi / Ejector Design to Boost Water Flow using a Pump

    I have a water tank fed from a piping system that has very low head in it. As a result flow tends to be low. See sketch below. I am thinking of ways to boost the flow. I already have a centrifugal pump at the site. Could I use its flow to boost the flow from the incoming pipe via a venturi /...
  48. caters

    Solar Still: Factors to Consider

    I now know that an insulator will not only keep heat in but keep heat from being conducted in the first place So my solar still is almost 100% metal including the 2 valves. There is however 1 plastic pipe between the rain collector and the evaporator that is flexible. My solar still has several...
  49. Glurth

    How can I ensure even water flow to my garden?

    I would like to setup a subsurface irrigation system for my garden. I have several beds which, while I made each one perfectly level, are at different elevations (about 1 or 2 feet between each) . The source of the water will be a permanently mounted bucket, barrel or cistern of some kind...
  50. S

    Velocity of Fluid flow due to gravity

    I am designing a system for an engineering project at school. It's essentially a clock to be powered by water turning a mechanical system of gears (not generating electricity). Imagine a rectangular basin full of water placed at some height above the ground. There is a hole in the bottom...