VORTICES IN ANISOAXIAL SAMPLING INLETS

Thin-walled inlets are used in a variety of instruments and sampling d evices, quite often under anisoaxial conditions. An earlier study demo nstrated a new visualization technique for observing vortices formed i n a tubular inlet and indicated the effect of varying sampling rate an d angle. The effect of the flow pattern on gravitational setting, iner tial separation, and electrostatic interaction was observed. The prese nt study extends this work by examining these effects over a wider ran ge of sampling conditions and for some different inlet configurations. The vortices formed as a result of anisoaxial sampling change their l ocation and increase in intensity and size with increasing external ai r velocity. The vortices appear even for relatively short inlets. A fl ared inlet appears to eliminate the vortices for sampling angles of le ss than 90 degrees.