© Springer Science+Business Media B.V. 2010. In the present study a hybrid LES–RANS approach based on an explicit algebraic Reynolds stress model (EARSM) is suggested and evaluated. The model is applied in the RANS mode with the aim of accounting for the Reynolds stress anisotropy emerging especially in the near–wall region. Requiring solely the solution of one additional transport equation for the turbulent kinetic energy, the additional computational effort is marginal. A dynamically predicted interface location avoids the predefinition by the user and adjusts itself to the flow situation. As a test case including flow separation and reattachment, the flow over a periodic arrangement of hills is used.