Date

2023-1-26

Author

Koçak, Göktuğ

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Flight condition of aircrafts proximity to the ground, so-called “Ground Effect” (GE), is among one of the most recent research areas since the aerodynamic performance and stability of wing in ground effect (WIG) crafts significantly vary due to the flow dynamics associated with the interaction between the wing and the surface. In the present study, ground effect of non-slender delta wings (DW) and reversed delta wings (RDW) at static ground effect (SGE) condition in the absence of heave and pitch motion was investigated experimentally. The SGE condition was simulated with both static ground and dynamic ground conditions using an elevated ground system as well as a moving belt mechanism. The intensity of the GE and the stability characteristics of the wings were examined using force and moment, and surface pressure measurements to characterize the flow field both quantitatively and qualitatively. The results of the present study indicate that the effect of ground has substantial impact on both aerodynamic performance and stability of the delta and reverse delta wings. As the height of the wing decreases, both drag and lift forces increase where these effects were observed to be more pronounced for higher angles of attack. The presence of ground affects the longitudinal positions of the aerodynamic centers over the wing chord, hence results in interchanging stability characteristics varying with both height and angle of attack. The ground boundary condition tremendously affects the ground effect behavior such that dynamic ground condition results in larger areas under the lift-to-drag ratio versus angle of attack curve compared to OGE cases rather than increased peak values observed for the static ground condition whereas reduced slopes for the aerodynamic coefficients in line with different aerodynamic center positions on longitudinal axis are witnessed for both Belt On and Belt Off cases compared to the static ground condition, which might be considered as the footprints of dynamic pressure loss and flow angularity changes due to the ground boundary condition.

Subject Keywords

Ground effect, Delta wing, Reversed delta wing, Unsteady aerodynamics, Experimental aerodynamics

URI

https://hdl.handle.net/11511/102036

Collections

Graduate School of Natural and Applied Sciences, Thesis