Re-design of ARL/HLF (Heated Laminar Flow) body nose region

The ARL (Penn State Univ.'s Applied Research Lab.) Heated Laminar Flow (HLF) body is a streamlined body with a pointed nose. One of the experimental objectives for the ARL/HLF body is to provide for limited (low flow) stagnation point fluid ejection. Because fluid ejection can, in many instances, create laminar instabilities farther downstream, it is important to have a stagnation region geometry that helps minimize the enhancement of these instabilities. This is best achieved by using a geometry that supports a very favorable pressure gradient in the ejection region. Such a geometry has been specified for the ARL/HLF body. This report presents the important analytical results which led to this re-designed nose region. The results include potential flow pressure distributions, boundary layer development, and disturbance amplification ratios, for both the original and modified nose geometry. In the absence of fluid ejection, it is concluded that the laminar flow performance of the modified body will be the same as that of the original body.