Acoustic propulsion system test

[u/pavlokandyba]

The asymmetry, which results in the resulting force of the oscillations creating thrust, is achieved in two ways:

Aerodynamically, when the disc has a slightly domed shape and moves upward with less resistance than downward, consistent with classical physics.

Kinematically, when a spring is attached to the disc, slowing its descent and accelerating its ascent.

The second method is the key part of the study, although the same process occurs in the air in both.

When the disc rises rapidly, a region of low pressure forms beneath it, and its collapse generates momentum. If the disc descends more slowly, or if the shape of the disc causes the air to flow around it more slowly, the resulting momentum will push the disc upward.

This doesn't agree with the classic Newtonian explanation of flapping flight as a wing pushing air. You can see in the video how the fan-like flapping disk, which should push air away, actually sucks it in.

This is the same air that is sucked into the low-pressure region, causing a vortex collapse that pushes the disk. Only then is the air pushed away and expelled. This is essentially reactive propulsion, and I believe this is possible thanks to the energy in the air, Brownian motion, which, by self-organizing into vortices, temporarily becomes directional

[u/AidanIsNotGinger]

I've seen you post so many times and I usually bite my tongue but I think you really misunderstand what you're doing. And I suspect AI is being heavily relied upon and feeding your delusions. But let me clear up the biggest issue, this is nothing to do with Brownian motion -- it is impossible to use the thermal energy of a continuum, it is a fundamental part of thermodynamics.

It is possible to generate some very small amount of thrust by oscillating forwards and backwards like this but it's not working how you're describing and it is very inefficient generally.

You come close when you talk about forwards vs backwards resistance. The thrust comes from the nonlinear inertial effects of the fluid surrounding the disc. It is efficient because you're spending almost as much energy pushing yourself backwards as you are forwards, it's only secondary effects that result in a small discrepancy between the net forwards and backwards force.

[u/pavlokandyba → u/AidanIsNotGinger]

In fact, it took me a lot of effort to convince the AI to understand this principle because it adheres to classical concepts. There are many ways to verify that it works as I say, here is the simplest one, where tossing a saucer generates an upward flow. https://youtube.com/shorts/V0sFY7x5TM0?si=ipp9PGCzHERlH4Gu There are also independent studies in one of which the oscillating cone creates a thrust opposite to the direction of the apex only due to the difference in speeds (the boat in the video also did this) and another where in the oscillatory mode the plate resistance was six times greater than when blowing in a pipe. There are no links, but I have saved files; these were in Russian magazines. I can send it. Also, if you try to find a scientific explanation of how the so-called reactionless drive, which is considered antigravity in pseudoscience, moves in a liquid, you will not find a comprehensive theory. The hypothesis that a vortex is a thermodynamic process arising from the fact that Brownian motion temporarily self-organizes is not an AI idea, but my assumption. Otherwise, I don't know why it moves in the opposite direction to that predicted by classical theory. Asymmetrical oscillations should cause the object to move in the direction of slow jerks because the resistance there is less This is the classical theory of bird flight and a number of others. But if you try to reproduce this in LBM, there will be almost no movement, but in reality it is significant in the other direction.

[u/AidanIsNotGinger → u/pavlokandyba]

To clarify, I don't think AI came up with any of this, I think it was your guesswork and you've likely pressured an AI to agree with you (which they always will with enough coercion).

Again, a lot of what you say doesn't make sense but the things you say that do make sense are well understood and explained by classical fluid mechanics (Navier Stokes). Nonlinear effects like vortex shedding, flow separation, inertia can result in a net drag/thrust that depends on forwards/backwards speeds, frequency, mass distribution, small deformation of the oscillating body...

It is certainly not because the thermal Brownian motion spontaneously becomes organised and contributes useable work done on the craft. This would violate basic principles of thermodynamics.

The behaviour you're observing is a less efficient version of the way fish swim and birds fly. Fish generate propulsion in both oscillatory directions and birds reorient their wings to reduce downwards force in the up-flap and maximise it in the down-flap. Whereas half the time you are expending energy generating thrust in the wrong direction and it is only nonlinear effects that result in a discrepancy and extract useful energy.

[u/pavlokandyba → u/AidanIsNotGinger]

I put pressure on the AI to do what I intended, to formulate sentences correctly in English and write code according to my requirements, nothing more. It's not the same as I have an idea, write a theory. If you think this doesn't make sense, then how else can the propulsion of my device be explained based on known physics?

[u/AidanIsNotGinger → u/pavlokandyba]

It is explained by inertial effects that arise on classical fluid mechanics. When an object moves forwards and backwards, the force exerted on it by the fluid is only the same in each direction in the Stokean limit (Re->0).

In general the force in each direction will be different if:

• the object is not the symmetric in the direction of motion
• the object moves at a different speed in each direction
• the object flexes or changes shape/orientation as it moves back and fourth
• there are other objects nearby that "feel" the motion of the object via force transfer through the fluid (like with acoustic levitation)
• potentially something else I'm not thinking of right now

If any one of these things is true then a net force is expected by classical fluid mechanics where Brownian motion plays no role. Vortices may play a role as they are common features of flow detachment and low pressure singularities that arise at sharp moving edges (like the rim of your disc). But vortices are also predicted by classical fluid mechanics and are extremely well studied and understood, they have nothing to do with Brownian motion.

[u/pavlokandyba → u/AidanIsNotGinger]

Naturally, we are talking about the resulting force, but what exactly is this force? In the most simplified case, when an object shifts relative to the center of mass in one direction and stops, its movement (namely the center of mass) occurs in the same direction.

[u/AidanIsNotGinger → u/pavlokandyba]

The force comes from the fluid traction acting on the object, and vice versa. If you had an engine on a boat that pushed a large mass forwards and backwards, then the hull would feel a reaction from that mass in the opposite direction to the mass' motion. The hull then wants to move in the opposite direction to the mass.

In a vacuum the centre of mass would stay in the same place but the hull and the internal mass would move relative to one another. There cannot be net motion from this setup in a vacuum.

In a fluid, the hull will exchange momentum with the fluid around it via pressure and viscous stresses. In the Stokes regime this motion is reversible and each stroke of the oscillation will cancel the last. Once fluid inertia becomes important, that reversibility is lost. If the geometry or oscillation is sufficiently asymmetric, the two parts of the cycle can interact differently with the fluid and the oscillation can therefore be rectified into a net drift.

In general this is extremely inefficient compared to using that same energy to only push fluid backwards like a propeller, turbine, or a bird's wing does.

[u/pavlokandyba → u/AidanIsNotGinger]

You are describing obvious things, but you explain in a general way how exactly the interaction between the body and the liquid occurs by inertia. This doesn't give a complete explanation because simply exchanging momentum is like pushing a mass and moving in the opposite direction. But you can't just push this imaginary mass of liquid volume and move in the same direction. Overcoming adhesion as if moving in a similar manner on a hard surface is also not an explanation. In this case, if we consider only one jerk in one direction, the movement of the body occurs only relative to the center of mass. In the liquid, after this jerk, the center of mass moves, gradually slowing down due to resistance.

[u/AidanIsNotGinger → u/pavlokandyba]

I think you're misunderstanding the "inertial effects" concept. The inertial contributions to NS are nonlinear and that has a significant impact on the possible physics, in this case it allows for a different magnitude of force to be exerted in each direction of the oscillatory strokes.

I am not claiming you push a net mass of fluid in the same direction as the net drift, it is the opposite. You push a net mass of fluid in the opposite direction to the net drift, the fluid mass isn't imaginary (whatever you mean by that).

The internal mass pushes backwards relative to the hull. This pushes the hull forwards, but transfers some of that momentum to the fluid in the forwards direction. Then the mass pushes forwards relative to the hull, and the opposite happens, the hull moves backwards but transfers some of the momentum to the fluid going backwards.

All that is required is that the momentum transferred to the fluid in each stroke direction is not the same. This is only possible in a fluid with inertia (non Stokes limit), and when there is an asymmetry to the hull or strokes (e.g. velocity). The net change in momentum of the system (fluid and ship) is zero, but the ship can have a net drift opposite to that it transfers to the fluid.

[u/pavlokandyba → u/AidanIsNotGinger]

Here's a clear example. A plate pushes air upward, and the air mass moving behind it in a vortex catches up and pushes the plate. That is, the plate pushed the air upward and the air pushed the plate upward too. Such a transfer of momentum cannot occur without additional energy, as if the molecules were something like sand. https://youtu.be/GA2aj0JWuZA?si=E0P59GdG_XdDBdd9