- #1
LightningStrike
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I've been trying to non-dimensionalize a wave equation with a moving point source, but the peculiar properties of the delta function have confused me. How does one non-dimensionalize an equation with a delta function?
For example, the equation I'm looking at is something like the one below.
[itex]\nabla^2 P + 4 \pi A \delta(\vec{r} - \vec{r}_s) \sin(\omega t) = \frac{1}{c} \frac{\partial^2 P}{\partial t^2}[/itex]
The term with the (3D) delta function throws me off. The delta function has units of [itex][L]^{-3}[/itex]. By changing the inside of the delta function to non-dimensionalized vectors, the dimension of the delta function is lost, and the equation is no longer dimensionally consistent.
Any hints?
By the way, I know the solution for the unbounded case, but I'm interested in a certain geometry.
For example, the equation I'm looking at is something like the one below.
[itex]\nabla^2 P + 4 \pi A \delta(\vec{r} - \vec{r}_s) \sin(\omega t) = \frac{1}{c} \frac{\partial^2 P}{\partial t^2}[/itex]
The term with the (3D) delta function throws me off. The delta function has units of [itex][L]^{-3}[/itex]. By changing the inside of the delta function to non-dimensionalized vectors, the dimension of the delta function is lost, and the equation is no longer dimensionally consistent.
Any hints?
By the way, I know the solution for the unbounded case, but I'm interested in a certain geometry.
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