differential equation, Mathematics

Assignment Help:
Suppose a fluid (say, water) occupies a domain D? R^(3 ) and has velocity field V=V(x, t). A substance (say, a day) is suspended into the fluid and will be transported by the fluid as well as diffused within it; let u= u(x,t) be the concentration of the substance( mass per unit volume). Let Ø= Ø(x,t) be the concentration flux (mass per unit area per unit time, analogous to heat flux). Let B(x) be a ball of radius r > 0 contained in D. Derive the conservation law.

?_(B (x))¦u_(t ) dV= -?_(? B(x))¦?Ø.n_0 dS.?

Fick''s law for diffusion states that the concentration flux due to diffusion is proportional to the gradient of the concentration flux due to diffusion is proportional to the gradient of the concentration. Deduce that Ø= -k?+uV.
Apply the divergence theorem to the conservation law and substitute the flux formula to arrive at the diffusion- transport equation:
u_t= ?.(k?u)+ ?.(uV).
in the absence of diffusion (k=0), this is the higher- dimensional transport equation. If the fluid is motionless, it is called the diffusion equation.
Suppose a fluid (say, water) occupies a domain D? R^(3 ) and has velocity field V=V(x, t). A substance (say, a day) is suspended into the fluid and will be transported by the fluid as well as diffused within it; let u= u(x,t) be the concentration of the substance( mass per unit volume). Let Ø= Ø(x,t) be the concentration flux (mass per unit area per unit time, analogous to heat flux). Let B(x) be a ball of radius r > 0 contained in D. Derive the conservation law.

?_(B (x))¦u_(t ) dV= -?_(? B(x))¦?Ø.n_0 dS.?

Fick''s law for diffusion states that the concentration flux due to diffusion is proportional to the gradient of the concentration flux due to diffusion is proportional to the gradient of the concentration. Deduce that Ø= -k?+uV.
Apply the divergence theorem to the conservation law and substitute the flux formula to arrive at the diffusion- transport equation:
u_t= ?.(k?u)+ ?.(uV).
in the absence of diffusion (k=0), this is the higher- dimensional transport equation. If the fluid is motionless, it is called the diffusion equation.

Related Discussions:- differential equation

Describe graphing equations with a positive slope, Describe Graphing Equati...

Describe Graphing Equations with a Positive Slope? There are 3 steps to graphing a linear equation: 1. Identify and plot the y-intercept. 2. Determine the slope. Use the slope

Patrice has worked a certain how many hours has she worked, Patrice has wor...

Patrice has worked a certain amount of hours so far this week. Tomorrow she will work four more hours to finish out the week along with a total of 10 hours. How many hours has she

Interpretations of derivatives, Interpretations of derivatives. Exampl...

Interpretations of derivatives. Example:   Find out the equation of the tangent line to                                       x 2 + y 2   =9 at the point (2, √5 ) .

Determine the number of full withdrawals, A worker retires with a lump sum ...

A worker retires with a lump sum superannuation benefit of $500,000. She immediately invests this money in a fund earning 5% pa effective. One year after retirement she begins maki

Finite population correction factor or fpcf), Finite Population Correction ...

Finite Population Correction Factor Or Fpcf) If a specified population is relatively of small size and sample size is more than 5 percent of the population then the standard er

Mathematical laboratory, how to reverse positive digit number using mod fun...

how to reverse positive digit number using mod function

Calculate expected average time , A car was machine washes every car in 5 m...

A car was machine washes every car in 5 minutes accurately. It has been calculated that customers will arrive as per to a Poisson distribution at an average of 8 per hour. Calculat

Intersection of perpendicular tangents of hyperbola., If angle between asym...

If angle between asymtotes of hyperbola x^2/a^2-y^2/b^=1 is 120 degrees and product of perpendicular drawn from foci upon its any tangent is 9. Then find the locus of point of inte

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd