An investigation was performed to determine the aerodynamic and acoustic performance of the bifurcated 2D supersonic inlet during takeoff and approach flight conditions, and to compare these results indirectly to those of the axisymmetric supersonic inlet. The comparison is not direct since the centerbody position of the bifurcated 2D inlet is set at takeoff and approach position, where as the axisymmetric inlet’s centerbody position is not. The axisymmetric inlet’s aeroacoustic performance data is to serve as a reference to evaluate the bifurcated 2D inlet’s aeroacoustic performance. The inlets used in this study are 1/14 scale models designed for high speed civil transport aircraft. To provide the typical noise signature of a high bypass turbofan engine, a 10.4 cm (4.1 in.) turbofan engine simulator was used in conjunction with the supersonic inlets. The experiment was tested under static conditions. Steady state measurements of the inlet’s flow field and far field acoustic measurements of the fan noise were made to evaluate the aerodynamic and acoustic performance of the inlets respectively. The results show at approach fan speed (60 PNC), the bifurcated 2D inlet reduced circumferential distortion at the fan entrance by a factor of 1.7 compared to the axisymmetric inlet tested with auxiliary inlet doors closed and 1.5 compared to the axisymmetric inlet tested with auxiliary inlet doors open. At takeoff fan speed (88 PNC), the bifurcated 2D inlet reduced circumferential distortion by a factor of 1.5 compared to the axisymmetric inlet tested with auxiliary inlet doors open. The overall inlet total pressure recovery for the bifurcated 2D inlet at approach fan speed (60 PNC) is 97.6% which is 3.2 % higher than the axisymmetric inlet (94.4 %) with auxiliary inlet doors closed and 1.5% higher than the axisymmetric inlet (96.1%) with auxiliary doors open. Acoustic measurements were taken in a far field sector, 0°-110° from the inlet’s centerline axis. At takeoff fan speed (88 PNC), the bifurcated 2D inlet reduces the blade passing tone by an average of 9.6 dB over the (0-1 10°) far field sector compared to the axisymmetric supersonic inlet with the auxiliary inlet doors open. At approach fan speed (60 PNC), the bifurcated 2D inlet reduced the blade passing tone by an average of 8.8 dB compared to the axisymmetric supersonic inlet with auxiliary inlet doors open. When the axisymmetric inlet was tested with it’s auxiliary inlet doors closed at approach fan speed (60 PNC), the ‘choking effect’ changed the radiation pattern of the axisymmetric inlet such that only the rear sector far field (60°-110°) of the bifurcated 2D inlet is quieter than the axisymmetric inlet. On average, there was no appreciable difference in the blade passing tone for either inlet over the 0°-110° far field sector at this fan speed. / Master of Science