3D model trachea of a patient having bronchitis for CFD analysis. STL and OBJ files attached for download. The human trachea, commonly called the windpipe, is a tube about 11 cm long that carries air from the larynx to the two main bronchi of the lungs. It is supported by 16–20 C-shaped cartilage rings that keep it open during breathing while its inner lining of mucus and cilia traps and removes dust and microbes. The CAD model is by Gazi Md. Safi Rayhan (https://grabcad.com/gazi.md.safi.rayhan-1)