# SourcePDETerm SourcePDETerm[vars,f]

represents a source term with source coefficient and model variables vars.

SourcePDETerm[vars,f,pars]

uses model parameters pars.

# Details  • Source terms are used in a number of domains such as thermodynamics, acoustics, chemistry, physics and fluid dynamics.
• A source is typically used to model a source or sink.
• Adding a source with a source coefficient is the process of inserting or removing energy into a model by:
• • SourcePDETerm returns a differential operators term to be used as a part of partial differential equations:
• • SourcePDETerm can be used to model sources in equations with dependent variable , independent variables and time variable .
• Stationary model variables vars are vars={u[x1,,xn],{x1,,xn}}.
• Time-dependent model variables vars are vars={u[t,x1,,xn],{x1,,xn}} or vars={u[t,x1,,xn],t,{x1,,xn}}.
• The source term in context with other PDE terms is given by:
• • The source coefficient has the following form:
•  scalar • For a system of PDEs with dependent variables {u1,,um}, the source represents:
• • The source term in context systems of PDE terms:
• • The source coefficient is a tensor of rank 1 of the form where each value is a scalar that can be specified in the same way as for a single dependent variable.
• The source coefficient can depend on time, space, parameters and the dependent variables.
• The coefficient does not affect the meaning of NeumannValue.
• All quantities that do not explicitly depend on the independent variables given are taken to have zero partial derivative.

# Examples

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## Basic Examples(3)

Define a time-independent source term:

Define a time-dependent source term:

Solve a Poisson equation constructed from a diffusion and a source term:

## Scope(6)

Define a symbolic source term:

Define a 2D stationary source term:

Define a source term for multiple dependent variables:

Solve a Poisson equation with a source term:

Compute eigenvalues of a Poisson equation constructed from a diffusion and a source term:

Define a Helmholtz model:

Solve the Helmholtz equation with a source term:

Visualize the solution: