Convection: Realising a Trivial Thing?

  • Context: Undergrad 
  • Thread starter Thread starter vin300
  • Start date Start date
  • Tags Tags
    Convection
Click For Summary

Discussion Overview

The discussion revolves around the concept of convection, exploring its definition, mechanisms, and comparisons to pressure waves. Participants examine the underlying principles of convection, including density differences and the movement of particles in fluids, while questioning the similarities and distinctions between convection and pressure waves.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions the nature of convection, suggesting it may be similar to a pressure wave due to density differences causing mass flow.
  • Another participant argues against this similarity, stating that convection lacks a restoring force, which is essential for wave characteristics.
  • A different participant acknowledges that wave characteristics can be present in certain convection scenarios, such as Rayleigh-Bénard convection, but maintains that it is not equivalent to a pressure wave.
  • It is noted that convection involves the movement of gas or liquid molecules, influenced by temperature and pressure variations.
  • One participant highlights that in pressure waves, the average location of particles remains unchanged, while in convection, the motion can be nonlinear despite some forms maintaining a similar average location.
  • Another point raised is that pressure travel is based solely on properties of the medium, whereas convection is affected by external factors influencing motion.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the relationship between convection and pressure waves, with multiple competing views presented regarding their similarities and distinctions.

Contextual Notes

Some assumptions about the definitions of convection and pressure waves may be implicit in the discussion, and the nuances of different convection types are not fully explored.

vin300
Messages
602
Reaction score
4
Realising that all is not well when we're just moving not thinking, I began to think about a trivial thing which has been around me for too long. What actually is convection? If it is governed by difference in density causing the masses to flow, is this not atleast distantly, similar to a pressure wave?
 
Science news on Phys.org
You may want to ask a more specific (detail) question after having looked at wikipedia (or this ) .

I see little reason to re-hash what it says there.

It's not similar to a pressure wave: there is no restoring force, hence no wave character involved.
 
BvU said:
You may want to ask a more specific (detail) question after having looked at wikipedia (or this ) .

I see little reason to re-hash what it says there.

It's not similar to a pressure wave: there is no restoring force, hence no wave character involved.

There absolutely can be a wave character involved (e.g. Rayleigh-Bénard convection). However, it's not the same as a pressure wave.
 
Convection refers to some property (temperature, pressure, etc.) of a gas or liquid moving because the molecules of the gas or liquid themselves move.
 
In a pressure wave the average location of particles is the same, however, in some forms of convection too, the average location is the same, but motion is non linear. The temperature causes pressure that extends, whereas gravity effect differences cause forces that restore. I guess forced convection is farther from what could be seen an harmonic behaviour.
 
The clear distinction is that pressure travel is governed by a property purely possessed by the medium, while here it depends on properties of outside bodies that affect motion.
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
8K
Replies
6
Views
2K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 5 ·
Replies
5
Views
4K
  • · Replies 16 ·
Replies
16
Views
2K
Replies
0
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 3 ·
Replies
3
Views
4K