  In this paper, we investigate the modeling of sub-scale components of proper
orthogonal decomposition reduced order models (POD-ROMs) of
convection-dominated flows. We propose ROM closure models that depend on the
ROM residual. We illustrate the new residual-based data-driven ROM closure
within the variational multiscale (VMS) framework and investigate it in the
numerical simulation of a one-dimensional parameter-dependent
convection-dominated convection-diffusion problem. For comparison purposes, we
also investigate a streamline-upwind Petrov-Galerkin (SUPG) ROM stabilization
strategy and the standard Galerkin ROM (G-ROM). Our numerical investigation
shows that the new residual-based data-driven VMS-ROM is more accurate than
both the standard G-ROM and the SUPG-ROM.
