The hydrofoil weirs are a type of short-crested weirs that are designed, based on airfoil theory. This kind of weirs has some merits compared to the other types, such as high discharge coefficient, stability and submergence limit, and low fluctuations of pressure and water free-surface profile. The hydrofoil weirs with an angle of attack, looking like the ogee weirs, can be used as dam spillways. In the present study, models of hydrofoil weirs with different radius of the reference circle, relative eccentricities, cambers, angles of attack, and upstream slope angles, are applied to investigate the hydraulic characteristics of free and submerged flow over these weirs experimentally and numerically. The discharge coefficient of free and submerged flow and the weir threshold submergence are determined. Numerical simulations are performed using an open source, OpenFOAM v.4.0.1, CFD software. The interFoam solver is used to achieve the water free surface profiles and the SST k-? turbulent model applied for turbulence modelling of the flow field. In the present study, also, using the hydrofoil weir equation with an angle of attack, a continuous equation is presented for the upper and lower faces of ogee weirs. Consequently, the profiles of bed pressure along a hydrofoil weir matched on a specific ogee weir (design weir) is compared to that of the hydrofoil weirs with different relative eccentricities and cambers. Furthermore, a conformal mapping technique is applied to investigate the flow around a symmetric hydrofoil weir and compared to the flow around a circular cylinder, where the potential and free vortex flows are combined. The discharge coefficient and velocity distribution are obtained using the Joukowsky transformation and fundamental theories of hydraulics. Keywords: Discharge coefficient, hydrofoil weir, Joukowsky transform, OpenFOAM software, Potential flow, Pressure profile, Velocity distribution.
