A detached eddy simulation modelling approach is presented for turbulent flow computations, which is based on the transport equation for turbulent kinetic energy, k (and thus termed k-DES model). The model coefficients in the RANS form are calibrated in wall-attached flow computations, and the LES mode is calibrated in the simulation for decaying, homogeneous, isotropic turbulence. To combine the near-wall RANS mode with the off-wall LES mode, the RANS-LES interface is accomplished by means of an adaptation of turbulent length scales invoked in both the production term and the dissipation term of the k-equation. Examples presented for the modelling validation include a fully developed channel flow, a periodic hill flow and a three-dimensional axisymmetric hill flow. The results are compared with available DNS, LES and experimental data, showing reasonable agreement.