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One of the focused problem in airway flow simulation is pulmonary airways modeling. There are two kind of Lung models, one is created anatomically based on bronchial data and second is realistic model which is created based on CT scan images. Unfortunately cause of modeling process or simplification cause of restriction of CPU and time, the result model is different from a really pulmonary airways. Anatomically model are many simplification and realistic model from CT scan have major limitation in CT image resolution and smoothing stage of make out the 3D model. Anyway the lung has many rough and the first thing that is vital on this way is cartilage rings as macro scale roughness. So the presented work, compared the airflow in both simple and modified Horsfield model by cartilage rings in term of time averaged wall shear stress which are important in engineering of Cell-Fluid Interactions (CFI). This is shown that cartilage rings affected the trachea and second generation of brunches so this is not reasonable to neglect the cartilage rings.