Optimal combination of spatial basis functions for the model reduction of nonlinear distributed parameter systems

Spectral methods are among the most extensively used techniques for model reduction of distributed parameter systems in various fields, including fluid dynamics, quantum mechanics, heat conduction, and weather prediction. However, the model dimension is not minimized for a given desired accuracy because of general spatial basis functions. New spatial basis functions are obtained by linear combination of general spatial basis functions in spectral method, whereas the basis function transformation matrix is derived from straightforward optimization techniques. After the expansion and truncation of spatial basis functions, the present spatial basis functions can provide a lower dimensional and more precise ordinary differential equation system to approximate the dynamics of the systems. The numerical example shows the feasibility and effectiveness of the optimal combination of spectral basis functions for model reduction of nonlinear distributed parameter systems.

► We build optimal spatial basis functions for the model reduction of nonlinear DPSs. ► New basis functions are chosen by linear combination of spectral basis functions. ► The linear transformation is derived by minimizing a simplified error function. ► Lower order ODE systems are obtained via the optimal basis function combination.