Graduate What is the packet speed in the discrete case?

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The discussion revolves around a problem involving the dynamics of expanding bubbles, specifically simple bubbles (S) and vector bubbles (V), both expanding at a constant speed c. Key questions arise about the meaning of "reissued" bubbles upon contact and the implications of their interactions, particularly when S and V bubbles touch. The concept of packet speed v in a discrete space is questioned, alongside the initial conditions and sizes of the bubbles. Participants emphasize the need for clarity on how these interactions lead to a constant average velocity for the bubble system. Ultimately, the thread concludes with a suggestion for the original poster to reflect on these questions to develop a model for further investigation.
intervoxel
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I've been struggling with the problem below for some time. It is not a homework.

A simple bubble S is a spherical surface that expands with constant speed c. A vector bubble V also expands with the same constant speed c. There is a 3d vector associated with a V.

If two S bubbles touch, they are both reissued at the contact point, while two V bubbles never interact.

If an S and a V touch, they are reissued at the point where the line defined by the vector of V, passing through the origins, pierces the respective spherical surface.

Initially, a number of NS of simple bubbles and NV vectorial ones are randomly distributed in a given volume. The vectors are also random but biased in a preferred direction.

As the system evolves, it is supposed that the bubbles move as a packet with constant speed v at the direction of the resultant vector of all the V's vectors.

The space is either continuous or discrete, that is, we have two distinct cases.

What is the packet speed v in the discrete case?

Thanks for any help.
 
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intervoxel said:
I've been struggling with the problem below for some time. It is not a homework.
intervoxel said:
A simple bubble S is a spherical surface that expands with constant speed c.
What is it that increases at c: radius, area, volume or something else?

intervoxel said:
A vector bubble V also expands with the same constant speed c. There is a 3d vector associated with a V.
Presumably this means the length of the vector increases at c.

intervoxel said:
If two S bubbles touch, they are both reissued at the contact point, while two V bubbles never interact.
What does 'reissued' mean? What happens if the 'reissued' bubbles touch or intersect with each other or some other bubbles?

intervoxel said:
If an S and a V touch, they are reissued at the point where the line defined by the vector of V, passing through
the origins, pierces the respective spherical surface.
What does 'reissued' mean? What does 'passing through the origins' mean?

intervoxel said:
Initially, a number of NS of simple bubbles and NV vectorial ones are randomly distributed in a given volume. The vectors are also random but biased in a preferred direction.
What are the initial sizes of the 'bubbles'? How are intersections dealt with?

intervoxel said:
As the system evolves, it is supposed that the bubbles move as a packet with constant speed v at the direction of the resultant vector of all the V's vectors.
Why do you suppose that the random interactions you have (partially) described would result in a constant (average) velocity?

intervoxel said:
The space is either continuous or discrete, that is, we have two distinct cases.
What does a 'discrete' space mean?

intervoxel said:
What is the packet speed v in the discrete case?
You need to go away and think about the answers to the questions I have asked, then you can build a model of your system and investigate how it evolves yourself.
 
Last edited by a moderator:
A problematic post by the OP has been deleted, and they are on a temporary time-out from PF. Thread is closed.
 
Here is a little puzzle from the book 100 Geometric Games by Pierre Berloquin. The side of a small square is one meter long and the side of a larger square one and a half meters long. One vertex of the large square is at the center of the small square. The side of the large square cuts two sides of the small square into one- third parts and two-thirds parts. What is the area where the squares overlap?

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