This paper deals with numerical study based on the aerodynamics characteristics of modified circular cylinder. The main objective of the paper is to analyze the variation of drag coefficient, Strouhal number and base pressure coefficient due to different modifications, change in slit width and angle of attack. The analysis is done at subcritical Reynolds number value of 2100, the nominal diameter of the cylinder is 30mm. From the results, it is noticed that drag coefficient value reduces with increase in slit width. The Strouhal number increases because of decrease in the wake region which means decrease in drag coefficient, since drag coefficient and Strouhal number are inversely proportional. A decrease in base pressure coefficient is also noticed for the above case. Increase in drag coefficient is noticed on increasing the angle of attack from 0 to 90-degree. To substantiate the results of the numerical study, a flow visualization experiment has been conducted at a constant slit width at different cylinder orientations.