Vortices in Anisoaxial Sampling Inlets

Thin·walled inlets are used in a variety of instruments and sampling devices, quite often under anisoaxial conditions. An earlier study demonstrated a new visualization technique for observing vortices formed in a tubular inlet and indicated the effect of varying sampling rate and angle. The effect of the How patterns on gravitational settling, inertial separation, and electrostatic interaction was observed. The present study ex-tends this work by examining these effects over a wider range of sampling conditions and for some different inlet configurations. The vortices formed as a result of anisoaxial sampling change their location and increase in intensity and size with increasing external air velocity. The vortices appear even for relatively short inlets. A Hared inlet appears to eliminate the vortices for sampling angles of less than 90°.