Advection vs Convection: 11 Critical Facts


There are many modes of transfer of heat, among which Advection and Convection are important. In this post, we are going to know Advection Vs. Convection.

Advection is a process in which hot air molecules move in a horizontal direction, whereas in Convection, molecules of hot air move in the vertical direction on the atmospheric surface.

Let us know in-depth the concepts of Advection Vs. Convection.

Advection: Definition

Advection is one of the essential Phenomena in which the molecules of heat transfer in a specified path.

Generally, the Advection process is defined as the movement of molecules of liquid or air from one surface to another in a horizontal way. It is also known as advection currents. The movement of molecules is in bulk quantity and depends on wind and ocean currents.

Similarly, let us know about convection.

Convection: Definition

Convection or convection currents is a multiphase process, which is a basic method of transferring heat.

Convection is one of the necessary processes in which hot molecules of fluid transfer; it occurs only in liquid and gas particles because there is enough space for movement for molecules in these two states of matter. It occurs due to continuous heating of the quantity.

Therefore, both convection and convection currents are the same.

Advection VS Convection

The necessary components of Advection VS Convection are as follows;

                    ADVECTION                   CONVECTION
 The movement of warm molecules of fluid in a horizontal manner is Advection.The movement of warm molecules of fluid in a vertical manner is Convection.
The horizontal motion of fluid molecules is more notable.The vertical motion of fluid molecules is comparatively less notable.
It can occur in both the troposphere and ionosphere.It has a limitation of transfer of heat up to the troposphere layer.
It occurs due to pressure and temperature differences.It occurs due to the thermal difference between the quantities.
Advection fog is one of the crucial mechanisms.The sea breeze and Land breeze, a cyclic process, is due to Convection.
The advection process can be experienced mainly near the ocean.The convection process can be experienced in all the appliances that work on heat.
Pressure and temperature are the main components.Temperature is the main component.
The local winds of Northern India, known as LOO, are due to Advection.Examples are heaters, boiling of water, etc.

These are some common and notable differences of Advection Vs. Convection.

Convection: How does it work?

Convection is a combined process of diffusion and advection heat transfer.

When we heat a fluid in a pan, the lower layer of the fluid first heats up and is less dense in nature. From the concept of buoyancy, we can say that the hotter component of fluid rises and replaces the colder part of the fluid. It is a cyclic process that repeats until all the pieces are at the same temperature.

It is how Convection occurs in fluids and transfers in a vertical direction.

Advection: How does it work?

Advection is the only process in which heat molecules transfer in a horizontal path.

The advection process is one of the essential mechanisms which maintains equilibrium in both the sea and atmosphere. The difference in temperature and pressure moves the bulk quantity of gas to reach an equilibrium state. The advective air move from higher temperature gradients to lower gradients. The wind is an example of Advection.

It is how Advection occurs in the fluid.

Convection current and Advection current

Both convection and advection current differ from each other.

  • A convection current is the cause of the rapid movement of liquid molecules when it is in the phase of boiling.
  • These currents are the cause of the heating up of the mantle of the earth’s core. The reason behind convection currents is the thermal expansion of fluids.
  • Advection currents help to maintain the phase of equilibrium in the ocean and atmosphere.
  • Advection fog, which is one of the essential mechanisms in the atmosphere, occurs due to advection current.

These are some of the uses of convection and advection current.

Convection and its types

The two main types of convection heat transfer are

  • Natural Convection – Natural Convection occurs when there is a difference in densities due to temperature gradients; it appears as a result of buoyancy. It is known as Natural Convection.
  • Forced Convection – Forced Convection occurs when many external appliances such as ceiling fans and water pumps are made to create Convection.
  • Examples of forced Convection are water geysers and heat exchangers.

These are the essential types of Convection.

Relation between forced Convection and Newton’s Law of cooling

The formula for the connection between forced Convection and Newton’s law of cooling is as follows,

P = dQ/dt = hA(T – T0 )

Here,

P refers to the rate of transfer of heat.

h is the coefficient used for the transfer of Convection.

A is the surface area of contact.

T is the temperature of the submerged object.

T0 is the temperature of the fluid in which Convection takes place.

Let us know the factors affecting the coefficient of heat.

Factors affecting the Co-efficient of heat transfer

The critical factors which influence the coefficient of heat transfer are as follows;

  • The density of the fluid.
  • Specific heat capacity of liquid and gas.
  • Values of thermal conductivity of fluids.
  • Nature of viscosity of liquids and gases.

Apart from the above factors, there are undoubtedly other factors that influence the heat transfer coefficient.

Advection and its types

There are two essential types of advection heat transfer, which are as follows;

  • CAA- Cold air advection is a process in which wind moves from a region of the colder surface to a warmer surface of air.
  • WAA- Warm air advection is a process in which wind moves from a region of the hotter surface to a less-colder surface of air.
  • Both the process happens regularly on the atmospheric surface.
  • It takes place between surfaces of different temperatures.

The advection fog is a result of these two types of Advection.

Examples of Convection and Advection

The real-life examples of Convection and Advection are as follows,

  • The wind is an example of advection heat transfer which is due to the difference in pressure of air molecules.
  • Advection fog is a mass of air molecules that is transferred from a region of hot air to an area of cold air.
  • Ovens can be a good example of convection heat transfer.

Geysers, heat exchangers, and all the appliances which work on heat experiences a vertical movement of molecules, i.e., Convection.

  • The freezing of a lake in winter is also an example of Convection.
  • When you light a candle, you can experience the convection process.

These are some real-life examples of Advection and Convection.

Frequently asked questions on Advection and Convection| FAQs

Define Heat?

Heat is an essential source of energy.

Heat is defined as the movement of the quantity of energy from one source to another through various processes.

What are the different modes of transfer of heat?

The essential modes of heat transfer are as follows;

  • Conduction
  • Convection
  • Radiation
  • Advection

What are the essential connections of heat transfer?

There are two main factors which through which transfer of heat takes place, they are

  • Series heat transfer
  • Parallel heat transfer

What is the direction of heat transfer is Convection?

The direct transfer of heat molecules is different in all the processes.

Convection is an important mode of heat transfer in which the warm molecules of fluid or moisture travel in a vertical direction from one place to another. The transfer of heat in Convection is a rapid process.

What is the direction of heat transfer in Advection?

Can define the process of movement of molecules through Advection both in physics and geography aspects.

In physics, Advection is defined as one of the crucial processes of heat transfer of hot air or warm fluid molecules from one surface area to another horizontal is called Advection.

What are convection currents?

A convection current is nothing but convection heat transfer.

Convection currents occur when the fluid or air molecules move from one area to another after heating, the movement is due to the difference in thermal gradients. Examples are campfires, boiling of fluid, etc.

Do Convection and Advection differ from each other?

Both Advection and Convection are entirely different processes.

In general, we can say that Advection occurs when there is a transfer of some material such as temperature or moisture by the velocity of matter/fluid. Whereas, Convection occurs when there is a difference in density which is due to temperature gradients.

What are the necessary conditions for Convection?

The crucial conditions to be noticed in Convection are as follows,

  • The Convection will be natural; it is also called free Convection
  • If there is a temperature difference, then it affects the density of the fluid.
  • The fluid molecule’s movement occurs when the significant components fall, and light elements rise high.

Raghavi Acharya

I am Raghavi Acharya, I have completed my post-graduation in physics with a specialization in the field of condensed matter physics. Having a very good understanding in Latex, gnu-plot and octave. I have always considered Physics to be a captivating area of study and I enjoy exploring the various fields of this subject. In my free time, I engage myself in digital art. My articles are aimed towards delivering the concepts of physics in a very simplified manner to the readers. Let’s connect through - LinkedIn: https://www.linkedin.com/in/raghavi-c-s-260a801b1 EMAIL ID: raghavics6@gmail.com

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