A parametric study is conducted for the control of a turbulent jet using a single unsteady minijet. A number of control parameters that influence the decay rate
$K$ of the jet centreline mean velocity are investigated, including the mass flow rate ratio
$C_{m}$, excitation frequency ratio
$f_{e}/f_{0}$ and exit diameter ratio
$d/D$ of the minijet to main jet, along with the duty cycle (
$\unicode[STIX]{x1D6FC}$) of the minijet injection. Extensive hot-wire, particle image velocimetry and flow visualization measurements were performed in the manipulated jet. Various flow structures have been identified, such as the flapping flow, non-flapping flow and that showing a manipulable thrust vector, depending on
$C_{m}$,
$f_{e}/f_{0}$ and
$\unicode[STIX]{x1D6FC}$. Empirical scaling analysis unveils that, prior to the minijet impingement upon the wall of the nozzle and the generation of turbulence, the relationship
$K=g_{1}$ (
$C_{m}$,
$f_{e}/f_{0}$,
$d/D$,
$\unicode[STIX]{x1D6FC}$) may be reduced to
$K=g_{2}$ (
$\unicode[STIX]{x1D709}$), where
$g_{1}$ and
$g_{2}$ are different functions and the scaling factor
$\unicode[STIX]{x1D709}=(\sqrt{MR}/\unicode[STIX]{x1D6FC})(d/D)^{n}$ (
$\sqrt{MR}\equiv C_{m}(D/d)$ is the momentum ratio and
$n$ is a constant that depends on
$\unicode[STIX]{x1D6FC}$) is physically the effective momentum ratio per pulse or effective penetration depth. Discussion is conducted based on
$K=g_{2}$ (
$\unicode[STIX]{x1D709}$), which provides important insight into the jet control physics.