## 5 Conclusions  
This paper presents the results of simulation and experimental research on the aerodynamic characteristics of an aircraft model with variable wing geometries in a folded configuration. During these studies, the General Dynamics F-111 \"Aardvark\" aircraft model was used. It was prepared using Solid Works 2022 software and then made with the use of 3D printer for experimental tests. Simulation studies were conducted employing the CFD method implemented in ANSYS Fluent software, and experimental tests were performed in a hydrodynamic tunnel. In both cases, the tests were carried out for the same medium (water) and scale, and a similar range of the angle of attack due to the risk of damaging the strain gauge. The aerodynamic coefficients of the force and moment were obtained, as well as the pathline vortex visualization. The quantitative CFD results are also available for the named zones of the model corresponding to individual aircraft components, which is a significant advantage of this method. The simulations cover a wide range of angles of attack, revealing essential aerodynamic phenomena such as airflow detachment and vortex behavior, especially in critical areas. On the other hand, in the hydrodynamic tunnel, experimental tests were conducted using real water and a specially prepared model of the aircraft with a measurement system. The results of these tests, including aerodynamic forces and moments coefficients, are also presented and compared with CFD computations. During the comparative analysis of results obtained using ANSYS Fluent software and experimental results from the hydrodynamic tunnel, the aerodynamic coefficient values were compared for angles of attack ranging from 0\({}^{\circ}\) to 30\({}^{\circ}\). The maximum value of angle of attack was limited by the technical constraints of the utilized strain gauge weight system in the hydrodynamic tunnel. Nonetheless, for the mentioned range of studies, the results obtained were very consistent. Slight discrepancies between the results obtained using the CFD method and those obtained from the hydrodynamic tunnel allow for the selection of a more convenient method for a given problem. Upon analyzing the discrepancies between the CFD simulation and hydrodynamic tunnel test results, the main conclusion is that, even if the CFD method does not provide the exact values backing up the tunnel results, it shows the tendency with great accuracy. There  
Figure 17: Comparison of the pitching moment coefficient (Cmy) values obtained in the hydrodynamic tunnel and with CFD. fore, the conclusions regarding the aircraft stability would be valid using both methods when recalculated to real scale and velocity; in other words, to the real Reynolds number. This comparison of the CFD results with the hydrodynamic tunnel tests contributes to the development of a research methodology in aerodynamics. The benefits of using CFD, such as accurately determining the contributions of individual structural elements for generating aerodynamic forces and moments, are emphasized. Simultaneously, hydrodynamic tunnel experiments validate the results and provide the visualization of the flow behavior under dynamic conditions. In summary, the article presents a comprehensive approach to aerodynamic research, leveraging the advantages of both CFD and hydrodynamic tunnel testing. This is a significant contribution to advancing knowledge in aerodynamics and enhancing our understanding of flow behavior under various flight conditions. Conceptualization, A.M. and P.K.-M.; methodology, A.M. and A.D.; software, A.D.; validation, A.M. and A.D.; formal analysis, A.M. and A.D.; investigation, A.M. and A.D.; resources A.M., A.D. and P.K.-M.; data curation, A.M. and A.D.; writing--original draft preparation, A.M., A.D. and P.K.-M.; writing--review and editing, A.M., A.D., P.K.-M. and S.K. ; visualization, A.M. and A.D.; supervision, A.D. and S.K. ; funding acquisition, S.K. All authors have read and agreed to the published version of the manuscript.