What is the difference between dispersion and diffusion?
Dispersion can be differentiated from diffusion in that it is caused by non-ideal flow patterns (i.e. deviations from plug flow) and is a macroscopic phenomenon, whereas diffusion is caused by random molecular motions (i.e. Brownian motion) and is a microscopic phenomenon. Dispersion is often more significant than diffusion in convection ...
fluid dynamics - What is the exact difference between diffusion ...
That is, convection is the sum of fluid movement due to bulk transport of the media (like the water in a river flowing down a stream - advection) and the brownian/osmotic dispersion of a fluid constituent from high density to lower density regions (like a drop of ink slowly spreading out in a glass of water - diffusion).
Difference between diffusion, dissipation and dispersion in …
2018年10月5日 · Praveen provided a good answer, I just suggest to see the numerical effects of diffusion and dispersion by using the modified wavenumber analysis for the linear wave equation discretized by first and second order FD in space.
Diffusion versus dispersion - Physics Stack Exchange
2023年5月27日 · Dispersion is a more general term that describes the diffusion-like expansion of a sharp moving front. It may be due to several mechanisms in addition to molecular diffusion, for example complex fluid motion, eddies, flow around obstacles and so on.
convection, diffusion, advection, dispersion - CFD Online
2007年5月18日 · 2. Velocity and diffusion coefficient (e.g. thermal conductivity) plays a major role in convection while in diffusion, only diffusion coefficient is necessary. Temperature difference etc. is needed in both the cases. 3. Energy carried by fluid is more in convection than in diffusion (recall Nusselt number) 4. Without diffusion, convection ...
Diffusion and dispersion relation - Physics Stack Exchange
2020年10月27日 · Indeed, in wave phenomena the dispersion relation has a clear interpretation in terms of the phase and group velocities. Another place where dispersion frequently comes in play is in discussing non-linear waves: e.g., solitons are often describes as an interplay between the dispersion and the non-linearity.
Diffusion vs Advection - Physics Stack Exchange
2018年4月1日 · $\begingroup$ In an example of diffusion; when ink is dropped in water , it then diffuses in water. But if the pressure exerted by water on ink, before it diffuses, was bigger than pressure exerted by the ink on water , then diffusion wouldn't have occured. So again there should be a pressure gradient in order for the diffusion to occur.
What is the difference between diffusion and dispersion?
2011年2月7日 · - a central or high order discretisation scheme (with no limiter) will have low numerical diffusion and high dispersion; - a limited discretisation scheme tries to have the best of both world. From a physical point of view, diffusion is the capacity of smoothing sharp interface: think you have two gas separated by a wall.
convection, diffusion, dispertion, advection - CFD Online
2006年3月15日 · Dispersion is the combination of convective, diffusive and body forces (e.g. electric fields) acting upon a scalar concentration. For instance we talk about smoke dispersion from a chimney stack, which is the result of convective (the wind blowing it), diffusive (smoke diffuses in air) and buoyancy forces (hot air rises).
Molecular vs Eddy Diffusion - Physics Stack Exchange
2020年1月20日 · Molecular diffusion: Fluids at rest and adequately resolved moving fluids. Molecular diffusion occurs due the thermal motion of particles. It is proportional to the difference in concentration and is generally assumed isotropic (any source of anisotropy can be attributed to macroscopic and not microscopic mechanisms) and often constant.