2
$\begingroup$

When filling water trough with hose I notice if the hose exit is pushed roughly perpendicularly against the bottom of the tank the hose will 'stick' to the bottom of the tank, what are the physics that 'stick' the hose in place?

$\endgroup$
1
$\begingroup$

It's the Bernoulli principle. The fast flow between the floor and the edges of the nozzle produce enough of a vacuum (pulling the nozzle toward the floor) that it counteracts the repulsion force from the pressure (pushing the nozzle away from the floor). In an extreme case, imagine a nozzle end that had a small opening (so there isn't much repulsive force) but a lot of surface area radiating out from that opening, causing a lot of force pulling the nozzle toward the floor.

$\endgroup$
  • $\begingroup$ So, looking at the Bernoulli Eqn, $$p_1+0.5\rho_1v_1^2+\rho_1gh_1=p_2+0.5\rho_2v_2^2+\rho_2gh_2$$, the exiting fluid velocity ($v_2$) causes the pressure just outside the hose nozzle ($p_2$) to be low? If right or wrong, can you provide a further description of how to see the pressure difference causing the nozzle to be pushed towards the floor and how this force due to the difference in pressure is greater than the repulsive force due to the fluid impinging upon the floor ($F=\rho Q v$)? $\endgroup$ – Armadillo Feb 5 '18 at 16:15

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.