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For example, regions of warmer low-density air rise, while those of colder high-density air sink. This creates a circulating flow: convection. Gravity drives natural convection. Without gravity, convection does not occur, so there is no convection in free-fall environments, such as that of the orbiting International Space Station. Natural ...
Gravitational time dilation is a form of time dilation, an actual difference of elapsed time between two events, as measured by observers situated at varying distances from a gravitating mass. The lower the gravitational potential (the closer the clock is to the source of gravitation), the slower time passes, speeding up as the gravitational ...
The coordinate time is the time that would be read on a hypothetical "coordinate clock" situated infinitely far from all gravitational masses (=), and stationary in the system of coordinates (=). The exact relation between the rate of proper time and the rate of coordinate time for a clock with a radial component of velocity is:
As a consequence, the fluid is displaced while the cooler fluid gets denser and the fluid sinks. Thus, the hotter volume transfers heat towards the cooler volume of that fluid. [2] Familiar examples are the upward flow of air due to a fire or hot object and the circulation of water in a pot that is heated from below.
Airflow, or air flow, is the movement of air. Air behaves in a fluid manner, meaning particles naturally flow from areas of higher pressure to those where the pressure is lower. Atmospheric air pressure is directly related to altitude , temperature , and composition.
Now, the work by the force of gravity is opposite to the change in potential energy, W gravity = −ΔE pot,gravity: while the force of gravity is in the negative z-direction, the work—gravity force times change in elevation—will be negative for a positive elevation change Δz = z 2 − z 1, while the corresponding potential energy change ...
For example, air and water; both are fluids and if we consider them together then they can be seen as a stratified fluid system. Density variations in the atmosphere profoundly affect the motion of water and air. Wave phenomena in air flow over the mountains and occurrence of smog are the examples of stratification effect in the atmosphere.
If the flow is Boussinesq (and the room is otherwise symmetrical), then viewing the cold room upside down is exactly the same as viewing the warm room right-way-round. This is because the only way density enters the problem is via the reduced gravity g′ which undergoes only a sign change when changing from the warm room flow to the cold room ...