Abstract Introduction Refractive-index-matched (RIM) silicone phantoms play a critical role in experimental biomedical fluid mechanics, enabling detailed investigations of complex flow phenomena in anatomically accurate geometries. However, providing transparent, patient-specific and non-compliant and compliant models for detailed experimental quantitative analysis of the flow field, i.e., with high-dimensional accuracy and minimal post-processing, remains a major challenge. Methods This work presents a scalable manufacturing workflow based on a wax-based lost-core casting technique. High-resolution wax printing enables the three-dimensional (3D) creation of both non-compliant and compliant silicone phantoms with smooth surfaces, fine structural details, and clean core removal. The method allows for modular assembly of large geometries, and it is demonstrated on three representative models, namely a patient-specific human airway model, a generic compliant bifurcation, and a compliant patient-specific thoracic aorta. Results Mechanical and geometric tests confirm that the compliant phantoms replicate physiologically relevant vessel properties, with a measured Young’s modulus of 1.71 MPa and wall thickness variations below 1%. The phantoms are integrated into flow circuits, and the velocity distribution in the phantoms is measured using volumetric 3D particle-tracking velocimetry (PTV) using the Shake-the-Box (STB) algorithm. Time-resolved measurements under steady and pulsatile inflow conditions reveal detailed flow structures and fluid–structure interactions in both non-compliant and compliant models. Conclusions The presented workflow enables reproducible, high-fidelity RIM phantoms for experimental studies of biomedical flows. Combined with advanced flow diagnostics, it provides a powerful platform for exploring pathophysiological mechanisms, validating simulations, and evaluating the performance of medical devices in realistic geometries.
Johanning-Meiners et al. (Fri,) studied this question.