The Gaster transformation, which determines the approximate relation betwee
n 2-D temporal and spatial amplification rates of wave disturbances, is ext
ended to the cases with the effects of heat transfer. By applying the expan
sion method, a modified Gaster transformation is presented. The numerical r
esults of plane Poiseuille flow show that the modified Gaster transformatio
n works well when there are heat transfer effects. (C) 2000 Elsevier Scienc
e Ltd.