A Methodology to Measure Aerodynamic Forces on Cylinders in Channel Flow

While the measurement of drag and lift forces on a body in external flow is common practice, the same cannot be said for aerodynamic forces on bodies in internal flows. The inherent difficulty in making force measurements on a body in an internal channel flow is decoupling the body from the bounding walls. The methodology presented in this paper uses a technique to overcome this constraint to accurately measure two components of force on a single cylinder within a single row array, with an aspect ratio (height-to-diameter ratio) of 1. Experiments were conducted with air over a range of Reynolds numbers between 7500 and 35,000 and for three different spanwise pin spacings. Experimental results indicated an increase in cylinder drag with a reduction in spanwise pin spacing. The gas turbine and electronics industries use cylinders or pin fins in internal flow channels to increase heat transfer augmentation through high turbulence and increased surface area. The flow fields in these obstructed channels are difficult to predict, so these measurements can be used to directly compare with predicted drag and lift forces.