Physics 34.1 Bernoulli's Equation & Flow in Pipes (11 of 38) Flow Continuity at a Junction

In this video I will how the flow of continuity changes at a junction in a pipe in terms of velocity and area of the pipes.

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[Moon___man]

helped me with physics class, now currently helping me think out my irrigation system lol

[JC-wxqg]

What happen if P3 is to atmosphere and P2 continue in the pipe ?

[upion]

Given A1, A2, A3, and v1,  "A1 v1 = A2 v2 + A3 v3" is 1 equation for 2 unknowns (v2 and v3). There must be a second equation to determine v2 and v3. What is that equation?

[rubahasan]

In the 3rd figure, will the angle between the two pipes and the main pipe affect the velocity?

[Tommybotham]

What if there was a 3rd outlet right at the junction (the corner turns into another junction)? How would that affect continuity?

[reallifemathsbyanshuman]

Sir u are very panchual on utube aap real analysis aur linear algebra for IIT jee karao

[dianarosedeguzman]

help me
oil flows through a 4.0 cm i.d. pipe at an average speed of 2.5 m/s. find the flow in m3/s and cm3/s

[asimmohammed]

What is the professor name, his teaching style is adorable and easily understood.

[djfedezaza]

How does the pressure change from the big pipe to the 2 smaller ones?

[robertamarinei]

Thanks for the nice explanation!
I have troubles to understand how you would write bernoulli's equation for the 3 pipe system? Would it be the same as you wrote it on the left side of the board, or would it become P1 +1/2 rho v1^2 + rho g h1 = P2 +1/2 rho v2^2 + rho g h2 + P3 +1/2 rho v3^2+ rho g h3?

Thanks a lot!

[walterharoldbishop]

but how do we calculate V2 and V3 if either is unknown??

[KSJR]

How would this result change with a compressible fluid (air)? Would the decreased cross-section cause a higher pressure and cause less air to flow in the thinner pipe?

[chisexton]

How about water flow from a single into a T formation with A remaining constant in the T sections?

Velocity halved?

I'm okay with that. I need to move water to some trees at rear of yard while not overwatering grass.

[ajikoshy]

Great video sir,

Need one help in the third scenario
If A1=A2=A3, H1=H2=H3 and if A3 line is closed at an X mtr distance. What will be the effect of flow caused when fluid flows from A1 to A2. Will there be turbulence created at the intersection causing reduced flow rate and pressure.

[Cristian_]

I'm building my car exhaust pipes, and I was looking for something like this to be explained. Thank you for the information

[sylviawaise]

Great video, thanks a lot! I just have one question:
If I understand it correctly even if I know A_1 and v_1 and also A_2 and A_3 I still have no way so know the velocities v_2 and v_3, I still need to measure at least one of those. Or is there a way to at least make a reasonable guess?

[yuningchen]

does the total pressure at A1 equal to the total pressure at A2 and A3, assuming there's no friction force along the pipe?

[ashbygeek]

You state that the change in pressure is due to increased friction losses due to increased velocity but... Bernoulli's equations explicitly assume a frictionless pipe.

edit - I wrote the following because I missed the tiny half-second where he stated his assumption that pipes A2 and A3 are smaller than A1. In that case his statement about friction losses is correct, though still a bit misleading without also mentioning the additional pressure change predicted by Bernoulli's equations. Below is the rest of my original comment with some corrections.

Also, velocity is not guaranteed to increase. In your equation "A1V1 = A2V2 + A3V3" you can set V1 = V2 = V3 to drop out the velocity figure and produce the equation "A1 = A2 + A3" which demonstrates the necessary relation between the pipes to achieve constant velocity between the pipes. For instance if the two pipes have half the cross-sectional area. In this case Bernoulli's equations predict the same pressure in pipes 2 and 3 as in pipe 1.

Now, if all three pipes are the same size: "A1 = A2 = A3" then the pipe size can be dropped out to produce "V1 = V2 + V3" in which case V2 and V3 must have lower velocity than V1. In this case friction losses (which bernoulli is ignoring) would actually be less than in a single pipe of that size.

[sanjesengineering]

For split up area, if v1 = 600cu./hr (diameter = 4") what will be the area for A2 so i get 189cu.m/hr?

[barnswardrowan]

didn't catch if A1 = A2 + A3 in split diagram, if not, would pressure have to be included in the equation?