In this thesis, investigations are carried out on a new passive method reducing tip leakage losses in unshrouded axial turbine blading. The focus lies on the variation of a design parameter of passive tip-injection. The main fields of research are experimental as well as numerical investigations. Gap width as well as inclination angle of the injection channel against the blade pressure side are chosen as the varying design parameters. Passive tip-injection reduces tip-leakage loss and inclined tip-injection is said to lead to further reduced tip-leakage loss. Experimental investigations are carried out at the linear cascade wind tunnel of the Institute for Energy Systems and Thermodynamics at the Vienna University of Technology. The used blade geometry corresponds to a tip section of a low pressure gas turbine blade with weak turning. Pneumatic pressure probes are used to measure the downstream flow field of the modified blade with an inclination angle of 45 at three characteristic gap widths. Taking into account measuring uncertainties, reduction of overall losses is the main quantity of interest. For numerical investigations, a model of the linear cascade used in the wind tunnel is employed in flow simulation using a suitable turbulence model. A one dimensional model is derived, which considers the injection channel acting as boundary conditions on the blade. Comparative interpretation with the measured overall losses gives information about applicability of the chosen calculation model. A detailed investigation of the computed results should bring insight to tip gap flow as well as to roll up of the tip-leakage vortex by using passive tip-injection. Measured and simulated tip-leakage losses will be compared with an analytical tip-leakage loss model. Finally, a simple analytic model is derived to investigate the influence of passive tip-injection on additional power through enlarged circumferential force due to system rotation.