4D flow MRI can be used to assess COA repair hemodynamics in-vivo, albeit, after surgery is performed. This study develops a modeling and validation framework for in-vitro COA hemodynamic assessment. Patient-specific in-vitro models were created representing pre- and post- repair COA aortic geometries. 4D flow was employed to assess model hemodynamics. A PIV protocol was developed to assess the validity of the 4D flow MRI results. PIV velocities qualitatively agreed with 4D flow MRI. In-vitro 4D flow MRI can be used as a predictive tool for COA that can be enhanced with PIV validation.