Heart diseases are the leading cause of death for men and women regardless the ethnic group [1]. Among all the heart diseases, the aortic (AV) and mitral (MV) valve diseases are most often encountered. It is hypothesized that close link between some of the valvular heart diseases and blood flow structure exists, for instance aortic valve calcification can be associated with complex structure and dynamics of wall shear stress at the aortic side of AV. The bicuspid aortic valve disease may cause aortic dilatation due to irregular hemodynamic caused by altered AV shape [2]. Therefore mathematical modelling blood flow is gaining popularity as a tool for prediction of occurrence probability and potential causes of valvular diseases for patient specific virtual environment. Moreover, it is believed assessment that hemodynamic modelling techniques can be applied for the assessment of quality and prediction of possible complication for non-invasive treatments of valvular diseases like transcatheter aortic valve replacement of mitral valve clipping. However, before mathematical modelling tools can be used in so sensitive application, the extensive validation of these tools need to be carried out. The paper concentrate on the experimental and numerical investigation of flow through biospheric aortic valve that is used in transcatheter aortic valve replacement. We focus on the unsteady structure of velocity field during operation of the valve, which was captured using time resolved particle image velocimetry (TRPIV) [3]. The velocity fields recorded on the dedicated experimental setup was compared against the results of numerical simulation and was used to quantify numerical model uncertainty. The present study was carried out within the framework of a research project financed by the National Science Centre under grant agreement DEC-2024/54/E/ST8/00100.