A computational investigation was performed to support the development
of a semispan model test capability in the NASA Langley Research Cent
er's National Transonic Facility, This capability is desirable for the
testing of advanced subsonic transport aircraft at full-scale Reynold
s numbers. A three-dimensional Navier-Stokes solver was used to examin
e methods to improve the now over a semispan configuration. First, a p
arametric study is conducted to examine the influence of the standoff
height on the flow over the semispan model, It is found that decreasin
g the standoff height improves the aerodynamic characteristics of the
semispan model. Next, active sidewall boundary-layer control technique
s are examined, Juncture region blowing jets, upstream tangential blow
ing, and sidewall suction are found to improve the flow over the aft p
ortion of the semispan model, Both upstream blowing and suction are fo
und to reduce the sidewall boundary-layer separation, The resulting ne
ar-surface streamline patterns are improved and found to be quite simi
lar to the full-span results. Both techniques, however, adversely affe
ct the pitching moment coefficient.