A computational survey focused on modifications to the casing near the rotor blade tip is carried out for the purpose of enhancing the performance and increasing the stall margin of a model turbofan stage in transonic operating conditions. The study is divided into three phases. During the first phase two types of casing treatments, inward protruding rings and circumferential grooves, were tested with relatively coarse grids. In the second phase, a grid resolution study is carried out with the results from this phase influencing the choices for the third stage. In the third phase, a comprehensive study is performed to examine the near-stall effects and stall-related behavior of the baseline case and a series of circumferential groove configurations
