  The present work studied various models for predicting turbulence in the
problem of injecting a fluid microjet into the boundary layer of a turbulent
flow. For this purpose, the one-equation Spalart-Allmaras (SA), two-equation
k-$\epsilon$ and k-$\omega$, multi-equation transition k-kL-$\omega$,
transition shear stress transport (SST), and Reynolds stress models were used
for solving the steady flow. Moreover, the transition SST, scale-adaptive
simulation (SAS), and detached eddy simulation (DES) models were used for the
transient flow. A comparison of the results indicated that the steady solution
methods performed sufficiently well for this problem. Furthermore, it was found
that the four-equation transition SST model was the most accurate method for
the prediction of turbulence in this problem. This model predicted the velocity
along the x-axis in near- and far-jet locations with about 1% and 5% errors,
respectively. It also outperformed the other methods in predicting Reynolds
stresses, especially at the center (with an about 5% error).
