Modelling Here we discuss the physical modelling and the mathematical framework. 1. Blood flow 1.1. Incompressible Newtonian fluid 1.2. Non-Newtonian model : Carreau-Yasuda law 2. Blood vessels 2.1. Elasticity 2.2. Dorsal aorta : Non-symmetric external tissue constraints 3. Cells under flow 3.1. Red blood cells 3.2. Circulating tumor cells 4. FSI : Mathematical framework 4.1. ALE (Blood flow - vessel walls) 4.2. Level-set Method (Cells under flow)