Coronary Heart Disease (CHD) is one of the top reason for many deaths around the world. The most commonly encountered disease state of CHD is atherosclerosis. Irrespective of the cause of narrowing down of the lumen area, it causes adverse effects to the blood çirculation. This will hinder the normal functioning of the human body and eventually lead to cardiac arrest. Most of the cases of coronary stenosis are intermediate grade. In a mild situation, medicine can be prescribed, but in severe cases, surgery is required. The cases which fall between mild and severe are a dilemma to the doctor for taking clinical decisions. The difficulty is resolved by a number called (Fractional Flow Reserve) FFR, which is found out by invasive technique. Due to the risk involved in the process, the alternate procedure of finding these number using a non-invasive method, CFD is performed. The patient-specific left anterior descending artery of a human arterial tree is numerically investigated based on computational fluid dynamics approach for quantifying the functional acuteness of stenosis in terms of FFR. The CAD models of patient-specific geometries are generated from multislice Computed Tomographic scan data obtained from various Indian patients. The simulation of the 3D model is done using finite volume-based solver in OpenFOAM. Similarly, the 1D stenosed artery is generated using an analytical equation, and the solution is obtained using locally conservative Galerkin method. A comparative study of FFR between 3D and 1D models is carried out in this study, and a correlation is proposed among 3D FFR, 1D FFR and different geometric attributes. The impact of different inlet boundary conditions on FFR is numerically investigated on the patient-specific 3D model. The pulsatile parabolic profile and Womersley profile at the inlet are generated using a reduced order 1D model and incorporated in the patient-specific geometry. The in-vitro experimental set-up of coronary circulation is developed, and the value of FFR are computed using different silicon model. The FFR value obtained by experiments is compared with numerical results. The intermediate coronary lesion is modelled experimentally using porous medium impedance to resemble micro-vasculature resistance.