- #1

Polarbear10

- 10

- 2

- Homework Statement
- Bernoulli equation / fluid flow

find height using Bernoulli equation

- Relevant Equations
- Bernoulli equation

Qv = V/t = A*V

Hi, everyone! Doing some fluid flow/Bernoulli tasks.

Ok, so the task is:

«A hose with a radius of 0,035m is connected to a nozzle, which reduces the radius of the hose to 0,018m (2). The hose carries (qv) 0,0075 m3/sec and the totalpressure (3) in the wide section (1) is 211 kPA. The density of the water is set at 1000 kg/m3.””

4: But the last task: “The nozzle is raised to a higher level. The pressure gauge (3) has a pressure on 241,2 kPa. How high was the nozzle raised”?

I'm struggling to see where I would start. What happens to the pressure in the pressure gauge (4)? Does it change when the nozzle is raised, or will it be the same as in task 3, with P2 being 186 kPa. Also, does the velocity change?

Here is a drawing of the situation,
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Ok, so the task is:

«A hose with a radius of 0,035m is connected to a nozzle, which reduces the radius of the hose to 0,018m (2). The hose carries (qv) 0,0075 m3/sec and the totalpressure (3) in the wide section (1) is 211 kPA. The density of the water is set at 1000 kg/m3.””

- 1: Task one is to find the dynamic pressure in the wide section. I found the velocity to be 1,95 m/s, using V1 = qv/A1. Then calculated the dynamic pressure using Pd = ½ * ρ * v^2 and got 1,89 kPa.
- 2: Second task was to calculate the static pressure. Using Pt = Pd – Ps, and found that PS = 209kPa.
- 3: Then the third task was to find the pressure in the pressure gauge (4). I then calculated the velocity2, using V2=A1*V1/A2, and got 7,37 m/s. I then used Bernouli-equation to calculate the pressure that would be in the gauge (4), and found P2 to be 186 kPa.

4: But the last task: “The nozzle is raised to a higher level. The pressure gauge (3) has a pressure on 241,2 kPa. How high was the nozzle raised”?

I'm struggling to see where I would start. What happens to the pressure in the pressure gauge (4)? Does it change when the nozzle is raised, or will it be the same as in task 3, with P2 being 186 kPa. Also, does the velocity change?

Here is a drawing of the situation,

**before**the nozzle gets lifted.