Will this water jet propulsion system design produce any forward thrust?
I am interested in building a very basic water jet propulsion system for a toy boat. Before I build it, I would like to know from a conceptual standpoint if this design of a water jet propulsion system will actually produce forward thrust.
Please refer to the conceptual drawing below of this water jet design. This drawing shows a top-down view of the toy boat.
An embedded motor-propeller will pull water into the pipe section coming from the stern of the toy boat and will at the same time be forcing water out of the pipe section going back to the stern of the toy boat. The force which should propel the toy boat forward should come from the dynamic pressure of the rushing water pushing against the inner walls of the two 90 degree elbow sections of the pipe. Will this particular design of a water jet produce forward thrust as expected?
Although I know that a traditional inline water jet system would be the more ideal thing to construct, I am very interested in finding out if a boat can be propelled using just the dynamic pressure(s) generated within a pipe.
mechanical-engineering fluid-mechanics propulsion marine-engineering
asked 10 hours ago
HRIATEXP
355
add a comment |
I am interested in building a very basic water jet propulsion system for a toy boat. Before I build it, I would like to know from a conceptual standpoint if this design of a water jet propulsion system will actually produce forward thrust.
Please refer to the conceptual drawing below of this water jet design. This drawing shows a top-down view of the toy boat.
An embedded motor-propeller will pull water into the pipe section coming from the stern of the toy boat and will at the same time be forcing water out of the pipe section going back to the stern of the toy boat. The force which should propel the toy boat forward should come from the dynamic pressure of the rushing water pushing against the inner walls of the two 90 degree elbow sections of the pipe. Will this particular design of a water jet produce forward thrust as expected?
Although I know that a traditional inline water jet system would be the more ideal thing to construct, I am very interested in finding out if a boat can be propelled using just the dynamic pressure(s) generated within a pipe.
mechanical-engineering fluid-mechanics propulsion marine-engineering
asked 10 hours ago
HRIATEXP
355
3
With the eccentric outward force to the right rear of the boat, the boat will possibly move in a circular direction to the left.
– Fred
8 hours ago
@ Fred, that is interesting. It makes me wonder if the toy boat's rudder was fixed in a hard-to-starboard position, would this result in the toy boat traveling in a forward/straight direction?
– HRIATEXP
9 mins ago
add a comment |
I am interested in building a very basic water jet propulsion system for a toy boat. Before I build it, I would like to know from a conceptual standpoint if this design of a water jet propulsion system will actually produce forward thrust.
Please refer to the conceptual drawing below of this water jet design. This drawing shows a top-down view of the toy boat.
An embedded motor-propeller will pull water into the pipe section coming from the stern of the toy boat and will at the same time be forcing water out of the pipe section going back to the stern of the toy boat. The force which should propel the toy boat forward should come from the dynamic pressure of the rushing water pushing against the inner walls of the two 90 degree elbow sections of the pipe. Will this particular design of a water jet produce forward thrust as expected?
Although I know that a traditional inline water jet system would be the more ideal thing to construct, I am very interested in finding out if a boat can be propelled using just the dynamic pressure(s) generated within a pipe.
mechanical-engineering fluid-mechanics propulsion marine-engineering
asked 10 hours ago
HRIATEXP
355
I am interested in building a very basic water jet propulsion system for a toy boat. Before I build it, I would like to know from a conceptual standpoint if this design of a water jet propulsion system will actually produce forward thrust.
Please refer to the conceptual drawing below of this water jet design. This drawing shows a top-down view of the toy boat.
An embedded motor-propeller will pull water into the pipe section coming from the stern of the toy boat and will at the same time be forcing water out of the pipe section going back to the stern of the toy boat. The force which should propel the toy boat forward should come from the dynamic pressure of the rushing water pushing against the inner walls of the two 90 degree elbow sections of the pipe. Will this particular design of a water jet produce forward thrust as expected?
Although I know that a traditional inline water jet system would be the more ideal thing to construct, I am very interested in finding out if a boat can be propelled using just the dynamic pressure(s) generated within a pipe.
mechanical-engineering fluid-mechanics propulsion marine-engineering
mechanical-engineering fluid-mechanics propulsion marine-engineering
asked 10 hours ago
HRIATEXP
355
asked 10 hours ago
HRIATEXP
355
asked 10 hours ago
HRIATEXP
355
asked 10 hours ago
HRIATEXP
355
asked 10 hours ago
HRIATEXP
355
355
3
With the eccentric outward force to the right rear of the boat, the boat will possibly move in a circular direction to the left.
– Fred
8 hours ago
@ Fred, that is interesting. It makes me wonder if the toy boat's rudder was fixed in a hard-to-starboard position, would this result in the toy boat traveling in a forward/straight direction?
– HRIATEXP
9 mins ago
add a comment |
3
With the eccentric outward force to the right rear of the boat, the boat will possibly move in a circular direction to the left.
– Fred
8 hours ago
@ Fred, that is interesting. It makes me wonder if the toy boat's rudder was fixed in a hard-to-starboard position, would this result in the toy boat traveling in a forward/straight direction?
– HRIATEXP
9 mins ago
3
3
With the eccentric outward force to the right rear of the boat, the boat will possibly move in a circular direction to the left.
– Fred
8 hours ago
With the eccentric outward force to the right rear of the boat, the boat will possibly move in a circular direction to the left.
– Fred
8 hours ago
@ Fred, that is interesting. It makes me wonder if the toy boat's rudder was fixed in a hard-to-starboard position, would this result in the toy boat traveling in a forward/straight direction?
– HRIATEXP
9 mins ago
@ Fred, that is interesting. It makes me wonder if the toy boat's rudder was fixed in a hard-to-starboard position, would this result in the toy boat traveling in a forward/straight direction?
– HRIATEXP
9 mins ago
add a comment |
1 Answer
1
active
oldest
votes
No, it would just create a torque couple and rotate the boat anticlockwise.
Let's say the small propeller has an output volume, q grams, and the distance between inlet pipe and outlet is 5cm.
The thrust and suction of each end of pipe.
$$ F = ρ q (v2 - v1) $$
say density of water is =1, and V1 is initially zero, for simplicity, even though it wouldn't affect the outcome either way.
$ F = qV2 and V2 = q/a :a is pipe's area$
And you have a torque,
$T = 5*q^2/a. $,
anticlockwise direction
This will turn the boat in place.
answered 8 hours ago
kamran
3,5891410
@ kamran, I can see now how this would be the case. I was thinking that the kinetic energy in the water that is being pulled in would cancel out the effect of the low static pressure within that section of the pipe.
– HRIATEXP
15 mins ago
add a comment |
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1 Answer
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active
oldest
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1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
No, it would just create a torque couple and rotate the boat anticlockwise.
Let's say the small propeller has an output volume, q grams, and the distance between inlet pipe and outlet is 5cm.
The thrust and suction of each end of pipe.
$$ F = ρ q (v2 - v1) $$
say density of water is =1, and V1 is initially zero, for simplicity, even though it wouldn't affect the outcome either way.
$ F = qV2 and V2 = q/a :a is pipe's area$
And you have a torque,
$T = 5*q^2/a. $,
anticlockwise direction
This will turn the boat in place.
answered 8 hours ago
kamran
3,5891410
@ kamran, I can see now how this would be the case. I was thinking that the kinetic energy in the water that is being pulled in would cancel out the effect of the low static pressure within that section of the pipe.
– HRIATEXP
15 mins ago
add a comment |
No, it would just create a torque couple and rotate the boat anticlockwise.
Let's say the small propeller has an output volume, q grams, and the distance between inlet pipe and outlet is 5cm.
The thrust and suction of each end of pipe.
$$ F = ρ q (v2 - v1) $$
say density of water is =1, and V1 is initially zero, for simplicity, even though it wouldn't affect the outcome either way.
$ F = qV2 and V2 = q/a :a is pipe's area$
And you have a torque,
$T = 5*q^2/a. $,
anticlockwise direction
This will turn the boat in place.
answered 8 hours ago
kamran
3,5891410
@ kamran, I can see now how this would be the case. I was thinking that the kinetic energy in the water that is being pulled in would cancel out the effect of the low static pressure within that section of the pipe.
– HRIATEXP
15 mins ago
add a comment |
No, it would just create a torque couple and rotate the boat anticlockwise.
Let's say the small propeller has an output volume, q grams, and the distance between inlet pipe and outlet is 5cm.
The thrust and suction of each end of pipe.
$$ F = ρ q (v2 - v1) $$
say density of water is =1, and V1 is initially zero, for simplicity, even though it wouldn't affect the outcome either way.
$ F = qV2 and V2 = q/a :a is pipe's area$
And you have a torque,
$T = 5*q^2/a. $,
anticlockwise direction
This will turn the boat in place.
answered 8 hours ago
kamran
3,5891410
No, it would just create a torque couple and rotate the boat anticlockwise.
Let's say the small propeller has an output volume, q grams, and the distance between inlet pipe and outlet is 5cm.
The thrust and suction of each end of pipe.
$$ F = ρ q (v2 - v1) $$
say density of water is =1, and V1 is initially zero, for simplicity, even though it wouldn't affect the outcome either way.
$ F = qV2 and V2 = q/a :a is pipe's area$
And you have a torque,
$T = 5*q^2/a. $,
anticlockwise direction
This will turn the boat in place.
answered 8 hours ago
kamran
3,5891410
answered 8 hours ago
kamran
3,5891410
answered 8 hours ago
kamran
3,5891410
answered 8 hours ago
kamran
3,5891410
3,5891410
@ kamran, I can see now how this would be the case. I was thinking that the kinetic energy in the water that is being pulled in would cancel out the effect of the low static pressure within that section of the pipe.
– HRIATEXP
15 mins ago
add a comment |
@ kamran, I can see now how this would be the case. I was thinking that the kinetic energy in the water that is being pulled in would cancel out the effect of the low static pressure within that section of the pipe.
– HRIATEXP
15 mins ago
@ kamran, I can see now how this would be the case. I was thinking that the kinetic energy in the water that is being pulled in would cancel out the effect of the low static pressure within that section of the pipe.
– HRIATEXP
15 mins ago
@ kamran, I can see now how this would be the case. I was thinking that the kinetic energy in the water that is being pulled in would cancel out the effect of the low static pressure within that section of the pipe.
– HRIATEXP
15 mins ago
add a comment |
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3
With the eccentric outward force to the right rear of the boat, the boat will possibly move in a circular direction to the left.
– Fred
8 hours ago
@ Fred, that is interesting. It makes me wonder if the toy boat's rudder was fixed in a hard-to-starboard position, would this result in the toy boat traveling in a forward/straight direction?
– HRIATEXP
9 mins ago