AME 341B Lab Experiments — Fluid Mechanics & Aerodynamics

This experiment characterized a turbulent free jet by mapping the velocity field of an air stream at multiple downstream distances using a pitot tube mounted on a 2-axis traverse system. The goal was to verify self-similar behavior in a fully developed turbulent jet and compare measured profiles against theoretical predictions.

The experimental setup used a steady nozzle flow with a pitot tube sweeping a planar cross-section of the jet cone at downstream distances of 1D, 5D, 7D, and 9D (where D is the nozzle diameter). At each position, velocity data was collected across the jet width and processed to extract the mean velocity profile. Reynolds number analysis confirmed fully turbulent conditions (Re ≥ 10⁴) at all measurement planes.

Data was normalized by the local centerline velocity and plotted against the similarity variable to verify self-similar collapse — a hallmark of developed turbulent jets. Turbulence intensity profiles were also extracted to identify the laminar potential core near the nozzle exit and the fully turbulent mixing region further downstream. Results matched the theoretical Gaussian profile and confirmed the hypothesis.

This experiment evaluated the aerodynamic performance of a NACA0010 airfoil placed inside a wind tunnel at steady freestream velocities of 10 m/s and 20 m/s. The primary goal was to compare two independent methods — the force balance method and the momentum balance method — for calculating lift and drag coefficients across a range of angles of attack.

Reynolds numbers were calculated to characterize the flow regime: Re = 61,200 ± 1,100 at 10 m/s and Re = 122,000 ± 600 at 20 m/s, both confirming fully turbulent, inertia-dominated conditions. A pitot tube traversed the wake behind the airfoil with data acquired through LabVIEW VI software. Lift and drag forces were also directly measured using an integrated force balance mounted in the tunnel.

Results showed lift coefficient increasing consistently with angle of attack, with higher Reynolds number yielding greater lift — consistent with theory. The force balance drag plots revealed a slight asymmetry at low angles, while the momentum balance approach provided more accurate and stable drag estimates by integrating the wake velocity deficit. Both methods were compared and sources of discrepancy discussed in the full report.