Table 1 Boundary conditions and corresponding basis functions that obey these boundary conditions.

From: A new approach for simulating inhomogeneous chemical kinetics

Boundary conditions

Basis function

\(\omega _n\)

\(\rho (0,t) = 0, \quad \frac{\partial \rho }{\partial x}(L,t) = 0\)

\(\sin (\omega _n x)\)

\(\frac{\pi }{L}\left( n + \frac{1}{2} \right)\)

\(\frac{\partial \rho }{\partial x}(0,t) = 0, \quad \rho (L,t) = 0\)

\(\cos (\omega _n x)\)

\(\frac{\pi }{L}\left( n + \frac{1}{2} \right)\)

\(\rho (0,t) = 0, \quad \rho (L,t) = 0\)

\(\sin (\omega _n x)\)

\(\frac{\pi }{L}n\)

\(\frac{\partial \rho }{\partial x}(0,t) = 0, \quad \frac{\partial \rho }{\partial x}(L,t) = 0\)

\(\cos (\omega _n x)\)

\(\frac{\pi }{L}n\)

  1. \(\rho (x,t) = 0\) is the Dirichlet boundary condition58 indicating that the concentration of the chemical species is zero at x (a perfect sink), and \(\frac{\partial \rho }{\partial x}(x,t) = 0\) is the Neumann boundary condition59 indicating that the net flux the chemical species is zero at x.