The paper presents the results of numerical modeling of turbulent airflow in a test room based on the vortex-resolving wall-modeled large eddy simulation approach. The room ventilation is provided by a plain air jet at Re = 5233. The jet is supplied from a slit placed at a side wall under the ceiling. The problem formulation reproduces the test experiment conditions (Nielsen et al., 1978, 1990) as completely as possible. Two configuration with various air supply slit width are considered. Calculations are carried out with the ANSYS Fluent software using the grid consisting of 48 million cells. The paper demonstrates that in the near-wall jet zone the computational results agree well with the experimental data, but visible disagreement is obtained in the recirculation flow region (occupied zone) with relatively low velocities.