Method and apparatus for predicting fluid flow through a subject conduit

A model-order reduction method is described for providing a fast fluid flow simulation model of fluid flow in a conduit such as a blood vessel with stenosis. A first method is described for generating a reduced generic numerical model (20) for predicting fluid flow characteristics of fluid flowing through a subject conduit (7'). In steps 11, 12 and 13, geometric and fluid-flow parameter data are derived from CT image scans for each sampled conduit 7 in a reference set. A 3D model is generated 13 for each sampled conduit 7. The geometric parameter data, the 3D model and the fluid flow parameter data are used to generate solutions to fluid dynamics (such as the Navier-Stokes) equations for each sampled conduit 7, and a full order model is created comprising the geometric parameters data, the fluid flow parameter data and the Navier Stokes solutions. A projection-reduction based, for example, on the Proper Orthogonal Decomposition - Discrete Empirical Interpolation Method (POD-DEIM) coupled with an offline/online splitting is used for the reduced-order description of geometric parameters, fluid parameters and fluid dynamic equations. The offline phase defines the constructors of the reduced-order model which are assembled based on the weights of the coefficients (reduced order parameters) identified in the offline phase. A second method is 30 described for using the reduced order model 20 to obtain solutions to Navier Stokes equations for the blood vessel 7' of a new patient (online phase).