MassConcentrationCondition [pred,vars,pars]
represents a mass concentration boundary condition for PDEs with predicate pred indicating where it applies, with model variables vars and global parameters pars.
MassConcentrationCondition [pred,vars,pars,lkey]
represents a thermal surface boundary condition with local parameters specified in pars[lkey].
MassConcentrationCondition
MassConcentrationCondition [pred,vars,pars]
represents a mass concentration boundary condition for PDEs with predicate pred indicating where it applies, with model variables vars and global parameters pars.
MassConcentrationCondition [pred,vars,pars,lkey]
represents a thermal surface boundary condition with local parameters specified in pars[lkey].
Details
- MassConcentrationCondition specifies a boundary condition for MassTransportPDEComponent .
- MassConcentrationCondition is typically used to set a mass species concentration on the boundary. Common examples include a mass species inflow condition.
- MassConcentrationCondition sets a specific mass species concentration on the boundary with dependent variable in [TemplateBox[{InterpretationBox[, 1], {"mol", , "/", , {"m", ^, 3}}, moles per meter cubed, {{(, "Moles", )}, /, {(, {"Meters", ^, 3}, )}}}, QuantityTF]], independent variables in [TemplateBox[{InterpretationBox[, 1], "m", meters, "Meters"}, QuantityTF]] and time variable in [TemplateBox[{InterpretationBox[, 1], "s", seconds, "Seconds"}, QuantityTF]].
- Stationary variables vars are vars={c[x1,…,xn],{x1,…,xn}}.
- Time-dependent variables vars are vars={c[t,x1,…,xn],t,{x1,…,xn}}.
- The mass concentration condition MassConcentrationCondition models .
- Model parameters pars as specified for MassTransportPDEComponent .
- The following additional model parameters pars can be given:
-
parameter default symbol"MassConcentration"
- 0
, mass concentration [TemplateBox[{InterpretationBox[, 1], {"mol", , "/", , {"m", ^, 3}}, moles per meter cubed, {{(, "Moles", )}, /, {(, {"Meters", ^, 3}, )}}}, QuantityTF]] - MassConcentrationCondition evaluates to a DirichletCondition .
- The boundary predicate pred can be specified as in DirichletCondition .
- If the MassConcentrationCondition depends on parameters that are specified in the association pars as …,keypi…,pivi,…, the parameters are replaced with .
Examples
open all close allBasic Examples (3)
Set up a mass concentration boundary condition:
Compute the mass concentration with model variables vars and parameters pars with a mass concentration of at the left boundary:
Set up the equation:
Solve the PDE:
Visualize the solution and note the sinusoidal mass change on the left:
Set up a system of mass concentration boundary conditions:
Scope (7)
Basic Examples (2)
Define model variables vars for a transient species field with model parameters pars and a specific boundary condition parameter:
Define model variables vars for a transient species field with model parameters pars and multiple specific parameter boundary conditions:
1D (1)
Model a 1D chemical species field in an incompressible fluid whose right side and left side are subjected to a mass concentration and inflow condition, respectively:
Set up the stationary mass transport model variables vars:
Set up a region :
Specify the mass transport model parameters species diffusivity and fluid flow velocity :
Specify a species flux boundary condition:
Specify a mass concentration boundary condition:
Set up the equation:
Solve the PDE:
Visualize the solution:
2D (1)
Model mass transport of a pollutant in a 2D rectangular region in an isotropic homogeneous medium. Initially, the pollutant concentration is zero throughout the region of interest. A concentration of 3000 is maintained at a strip with dimension 0.2 located at center of the left boundary, while the right boundary is subject to a parallel species flow with constant concentration of 1500 , allowing for mass transfer. A pollutant outflow of 100 is applied at both the top and bottom boundaries. A diffusion coefficient of 0.833 is distributed uniformly with a uniform horizontal velocity of 0.01 :
Set up the mass transport model variables vars:
Set up a rectangular domain with a width of and a height of :
Specify model parameters species diffusivity and fluid flow velocity :
Set up a species concentration source of 0.2 in length at the center of the left surface:
Set up a mass transfer boundary on the right surface:
Set up an outflow flux q of on the top and bottom surfaces:
Set up the equation:
Solve the PDE:
Visualize the solution:
3D (1)
Model a non-conservative chemical species field in a unit cubic domain, with two mass conditions at two lateral surfaces and a mass inflow through a circle with radius 0.2 at the center of the top surface, as well as an orthotropic mass diffusivity :
Set up the mass transport model variables vars:
Set up a region :
Specify a diffusivity and a flow velocity field :
Specify mass concentrations:
Specify a flux condition of through a regional circle on the top surface:
Set up the equation:
Solve the PDE:
Visualize the solution:
Material Regions (1)
Model a 1D chemical species transport through different material with a reaction rate in one. The right side and left side are subjected to a mass concentration and inflow condition, respectively:
Set up the stationary mass transport model variables vars:
Set up a region :
Specify the mass transport model parameters species diffusivity and a reaction rate active in the region :
Specify a species flux boundary condition:
Specify a mass concentration boundary condition:
Set up the equation:
Solve the PDE:
Visualize the solution:
Nonlinear Time Dependent (1)
Model a 1D non-conservative chemical species field with a nonlinear diffusivity coefficient and an outflow condition through part of the boundary, which is expressed as follows:
Set up the mass transport model variables vars:
Set up a region :
Specify a nonlinear species diffusivity and fluid flow velocity :
Specify an outflow flux of applied at the right end:
Specify a time-dependent mass concentration surface condition:
Set up an initial condition:
Set up the equation:
Solve the PDE:
Visualize the solution:
Applications (1)
Model mass transport of a pollutant in a 2D rectangular region in an isotropic homogeneous medium. Initially, the pollutant concentration is zero throughout the region of interest. A concentration of 3000 is maintained at a strip with dimension 0.2 located at center of left boundary, while a pollutant outflow of 100 is applied at both the top and bottom boundaries. A diffusion coefficient of 0.833 is distributed uniformly, but both horizontal and vertical velocity are spatial dependent:
Set up the mass transport model variables vars:
Set up a rectangular domain with a width of and a height of :
Specify model parameters species diffusivity and fluid flow velocity :
Set up a species concentration source of 0.2 in length at the center of the left surface:
Set up an outflow flux of on the top and bottom surfaces:
Set up the equation:
Solve the PDE:
Visualize the solution:
Tech Notes
Related Guides
History
Text
Wolfram Research (2020), MassConcentrationCondition, Wolfram Language function, https://reference.wolfram.com/language/ref/MassConcentrationCondition.html.
CMS
Wolfram Language. 2020. "MassConcentrationCondition." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/MassConcentrationCondition.html.
APA
Wolfram Language. (2020). MassConcentrationCondition. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/MassConcentrationCondition.html
BibTeX
@misc{reference.wolfram_2025_massconcentrationcondition, author="Wolfram Research", title="{MassConcentrationCondition}", year="2020", howpublished="\url{https://reference.wolfram.com/language/ref/MassConcentrationCondition.html}", note=[Accessed: 09-January-2026]}
BibLaTeX
@online{reference.wolfram_2025_massconcentrationcondition, organization={Wolfram Research}, title={MassConcentrationCondition}, year={2020}, url={https://reference.wolfram.com/language/ref/MassConcentrationCondition.html}, note=[Accessed: 09-January-2026]}