SJME KINEMATIKA Vol.
10 No.
2, 14 Oktober 2025, pp 265-276 https://kinematika.
id/index.
php/kinematika ANALISIS BERBASIS SIMULASI TERHADAP SIFAT AERODINAMIKA
AIRFOIL NACA 2412 DENGAN PENAMBAHAN ELEMEN FLAP DAN SLAT
SIMULATION-BASED ANALYSIS OF AERODYNAMIC PROPERTIES OF
NACA 2412 AIRFOIL WITH ADDITIONAL FLAP AND SLAT ELEMENTS
Okto Dinaryanto.
Bahrul Jalaali.
Syahrizal.
Abdul Haris Subarjo.
Dedet Hermawan Setiabudi.
Eli Kumolosari.
* 1,2,3,4,5,6Department of Mechanical Engineering.
Institut Teknologi Dirgantara Adisutjipto.
Yogyakarta.
Indonesia email: okto.
dinaryanto@itda.
, bahrul@itda.
, rizalsyah224@gmail.
abdulharissubarjo@gmail.
, dedethermawan@itda.
, elikumolosari@itda.
Received:
14 Maret 2025 Accepted:
3 September Published:
14 Oktober Abstrak Konsep awal proyek Easy-Fly adalah menciptakan pesawat STOL (Short Takeoff and Landin.
yang sangat ringan dengan drag dan kecepatan minimal.
Untuk mendukung tujuan ini.
CFD (Computational Fluid Dynamic.
atau komputasi dinamika fluida diaplikasikan dengan memvariasikan konfigurasi flap dan slat beralur tunggal serta sudut serang pada airfoil NACA 2412.
Model viscous yang digunakan dalam kasus ini adalah Spalart-Allmaras.
Variasi sudut serang () dimodifikasi pada rentang 0AOe20A.
Untuk model flap, sudut defleksi disesuaikan menjadi 30A dan 40A, dan slat ditambahkan ke konfigurasinya.
Berdasarkan hasil penelitian didapatkan bahwa defleksi flap 30A dan 40A menghasilkan nilai CL yang lebih tinggi pada sudut serang 0A.
Penggunaan desain flap dan slat pada airfoil NACA 2412 secara efektif menunda pemisahan aliran udara hingga mencapai sudut serang maksimum 24A.
Selain desain sistem high-lift pada airfoil NACA 2412, perubahan pada camber dan penyesuaian garis chord efektif menghasilkan peningkatan yang signifikan pada koefisien lift (CL), koefisien drag (CD), dan sudut stall.
Akhirnya, defleksi flap 30A lebih efisien daripada defleksi 40A dalam kondisi lepas landas.
Rata-rata persentase kenaikan CL/CD dari flap 30A ke 40A adalah 17,61%.
Kata Kunci: NACA 2412, flap, slat.
AoA.
CFD Abstract The original concept for the Easy-Fly project was to create an ultra-light STOL (Short Takeoff and Landin.
plane featuring minimal drag and speed attributes.
To support this goal.
CFD (Computational Fluid Dynamic.
was applied by varying the configuration of single-grooved flaps and slats and the angle of attack on the NACA 2412 airfoil.
The viscous model used in this case is SpalartAllmaras.
The variation of the angle of attack () was modified in the range of 0AOe20A.
For the flap model, the deflection angle was adjusted to 30A and 40A, and slats were added to the configuration.
Based on the results of the study, it was found that flap deflections of 30A and 40A resulted in higher CL values at an angle of attack of 0A.
The use of flap and slat designs on the NACA 2412 airfoil effectively delayed airflow separation until it reached a maximum angle of attack of 24A.
In addition to the high-lift system design on the NACA 2412 SJME KINEMATIKA Vol.
10 No.
2, 14 Oktober 2025, pp 265-276 https://kinematika.
id/index.
php/kinematika airfoil, changes in camber and effective chord line adjustments resulted in significant improvements in the lift coefficient (CL), drag coefficient (CD), and stall angle.
Finally, a 30A flap deflection was more efficient than a 40A deflection in takeoff conditions.
The average percentage increase in CL/CD from a 30A to a 40A flap was 17.
Keywords: NACA 2412, flap, slat.
AoA.
CFD DOI: 10.
20527/sjmekinematika.
How to cite: Dinaryanto.
Jalaali.
Syahrizal.
Subarjo.
Setiabudi.
, & Kumolosari.
AuSimulation-Based Analysis of Aerodynamic Properties of NACA 2412 Airfoil with Additional Flap and Slat ElementsAy.
Scientific Journal of Mechanical Engineering Kinematika, 10.
, 265-276, 2025.
INTRODUCTION
Aircraft wings are designed to produce sufficient lift to meet design requirements, thereby enhancing efficiency and cost-effectiveness in terms of travel distance and time.
The original concept for the Easy-Fly project was to create an ultra-light STOL (Short Takeoff and Landin.
plane featuring minimal drag and speed attributes.
The design and examination conducted on the STOL aircraft concentrate on a high-lift mechanism.
The flaps and wing slats are designed to be retracted, minimizing drag during flight and achieving a very high maximum lift coefficient during takeoff and landing, which is characterized by low takeoff speeds.
Aerodynamics is the study of the air movement, especially when it interacts with a solid object, such as an airplane wing.
This study is based on aircraft performance.
aerodynamic analysis, understanding wing performance is a fundamental aspect of research.
The basic shape of the wing depends on its primary use.
For example, symmetric wings are commonly used for tails, and asymmetric wings generate lift on aircraft wings.
thorough understanding of wing sections: including a summary of the airfoil data, is highly advantageous as an initial move prior to broadening the analytical scope to its 3D Generally, analysis can be done in three ways: analytical solutions, experiments, and numerical approximations.
It is important to note that analytical solutions are primarily effective for addressing specific, fundamental, and relatively simple problems.
However, experimental approaches are often expensive and difficult to conduct.
Conversely, aerodynamic numerical simulation offers a dependable approach to addressing the issues mentioned above.
Currently, numerical simulation provides a reasonable means for detailed analysis of the flow around the aircraft.
Previously, experimental and numerical studies were carried out.
As demonstrated in previous studies, experimental tests were used to evaluate the aerodynamics of the wing.
According to research, the flow characteristics of an aircraft wing are typically obtained as pressure and velocity distributions, as well as the drag and characteristic of lift.
Generally, numerical research should be done in advance to reduce the cost and time of testing.
CFD
(Computational Fluid Dynamic.
analyses are commonly conducted to investigate aerodynamic behavior.
As reported by references, one of the CFD models is SpalartAllmaras (S-A) equation, widely used in aerospace applications.
,6,.
The model was reliable, reasonably stable, and showed good numerical convergence in some aerodynamic The S-A model calculates the kinematic viscosity transport equation but does not consider length scale calculations related to shear layer thickness.
Based on earlier research.
CFD has proven to be a powerful technique for understanding physical aerodynamic characteristics.
However, little study has been conducted to provide a coherent understanding of the wing aerodynamics of high-lift system simulations, and this work tries to fill those gaps .
The subsequent points offer a concise summary of this task.
Initially, this research aimed to present the best CFD analysis methods for studying aerodynamic properties.
To evaluate the aerodynamic characteristics and SJME KINEMATIKA Vol.
10 No.
2, 14 Oktober 2025, pp 265-276 https://kinematika.
id/index.
php/kinematika achieve the required numerical accuracy, the Spalart-Allmaras (S-A) turbulence model was This model was chosen due to its low computational cost and its suitability for external aerodynamic flows.
To validate the numerical model, the simulation outcomes are compared with the results from wind tunnel experiments.
Fourth, a numerical study was conducted on the addition of flaps and slats to the wing for lift-drag behavior.
This study used the NACA 2412 airfoil.
Modifications to the angle of attack () and the deflection angles of the flaps and slats were carried out to evaluate aerodynamic performance.
Additionally, this study aims to enhance the evaluation of data-driven turbulence models for aerodynamic assessment.
RESEARCH METHODOLOGY
Geometry Model This work delved into the study of wing characteristics to aerodynamic properties.
two-dimensional .
D) numerical modeling method was employed.
The shape of NACA 2412 utilized was derived from publicly available information from the 4-digit NACA archive .
To verify the reliability of the existing CFD model for airfoil analysis, flaps and slats were added to the airfoil.
The configuration applied in this study is presented in Figure 1.
Figure.
Standard NACA 2412 .
Flap design .
Slat design The mathematical equation of the fluid analysis was conducted using mass and transport governing equations.
The continuity and momentum equations, which form the basis of the governing equations, are described below.
SJME KINEMATIKA Vol.
10 No.
2, 14 Oktober 2025, pp 265-276 https://kinematika.
id/index.
php/kinematika Conservation of mass yuiyuU yu.
uUy.
= 0
Conservation of momentum yui.
uUy.
ON.
uUycycO] = OeON.
ycE ON.
where A is the gas density.
V is velocity, and E is shear stress tensor.
Equation 1 shows the conservation of mass which used in the simulation as a basic condition for solving the problem.
It is related to the accuracy of the results, solution stability, and also mesh design.
Equation 2 shows the conservation of momentum, which is related to the results of lift and drag force of the airfoil.
At this stage, simulation parameters including the shape of the solid surface, airflow velocity, drag force, wall treatment, and flow regime were defined.
The values of the known turbulence modeling constants were obtained.
Here, the angle of attack .
variations were modified in the range of 0A-20A.
For the flap model, the deflection angle was adjusted to 30A and 40A, and a slat was added to the configuration.
Computational setup Meshing plays a crucial role in the simulation, as a finer mesh generally leads to more accurate results.
The mesh is divided into many cells, and the governing equations will be solved in each cell.
Therefore, the mesh around the airfoil is finer than that to understand the aerodynamic behavior around the airfoil.
It is critical because a lack of convergence and discretization methods can lead to poor simulation results.
The mesh used in this study is an unstructured grid with the All-Triangles Method type with additional Refinement, which refines the grid around the airfoil, as shown in Figure 2.
Figure 2.
Meshing all triangles method The influence of the flap and slat was accounted for by increasing the number of mesh elements on the flap structure.
The mesh used exhibited a high level of smoothness, with the center span angle and smoothing controlled via height and smoothness parameters.
The mesh quality is seen based on the mesh metrics in skewness with the number of elements The number of elements was obtained after the Grid Independence Test (GIT) step, as can be seen in Table 1.
The target of skewness is 0.
9 (Defaul.
, so the skewness is expected to be close to the target.
Table 2 shows the mesh quality used for the computational study.
SJME KINEMATIKA Vol.
10 No.
2, 14 Oktober 2025, pp 265-276 https://kinematika.
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php/kinematika The absolute criteria of the residual monitors were 10e-5 and the number of iterations was 2000 since these numbers showed the convergence graph.
Table 1.
Results of GIT Number of Elements CL/CD Table 2.
Mesh quality Mesh Metrics Skewness Min 1,4477e-007 Max
0,5459
Average 4,6471e-002 Standard Deviation 4,7408e-002 A CFD investigation was conducted using ANSYS-Fluent Student.
The computational domain was large enough to effectively observe the wind effects on the airfoil body.
shown in Figure 3, the airfoil was positioned at the center of the domain within an atmospheric setup.
During the solver stage, boundary conditions and input parameters were specified, with the airflow velocity set to 20 m/s.
Figure 3.
Computation domain and setup boundary conditions In addition to setting steady-state and pressure-based solutions, numerical discretization was used.
The vorticity-based and curvature correction addition was applied to the viscous S-A model, and the correction value was held constant by 1.
The airflow was defined in the subsonic domain, the fluid was an ideal gas, and there was no heat transfer The surface of the airfoil was subjected to the no-slip wall boundary condition.
The zero pressure and uniform velocity were established, and the turbulence properties at the inlet were configured to have a turbulence intensity of 5%.
Table 3 presents the simulation setting parameters.
A constant pressure condition with a zero-velocity gradient was applied at the outlet, while open boundary conditions were set for the top and bottom walls of the domain.
The pressure-velocity coupling was handled using a coupled algorithm with second-order spatial Moreover, to assess the aerodynamic characteristics, we initially concentrated on the standard airfoil.
The results were subsequently compared to the experimental Subsequently, we employed the flap and slat addition to assess the current method SJME KINEMATIKA Vol.
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php/kinematika on more intricate designs.
The parametric study was conducted on different orientations of airfoils and flaps, taking into account deflection and the inclusion of slats.
Table 3.
Setting parameter of the simulation Viscous Model
Spalart-Allmaras Model
Fluid
Air
Density 1,225 kg/m3 Viscosity 1,7894 x 10-5 kg/m-s Velocity Magnitude 20 m/s Temperature 288,16 K
Modified Turbulent Viscosity Method
Second Order Upwind
Chord length
RESULT AND DISCUSSION
Validation Study Validation is an important step in the simulation process to determine whether the simulation results match the physical reality.
The lift coefficient values obtained from the NACA 2412 airfoil CFD simulation were compared to the experimental results from wind tunnel data on the same airfoil profile, and to the Reynolds number values, as shown in Table It shows that the comparison of experimental and simulated CL values of NACA 2412 has an error value of <20%, which is 9.
88% for the angle of attack 0A-18A.
Therefore, the simulation results have a good agreement with the experimental results.
,12,.
Table 4.
The results of validation study AoA
Error
Experiment
Simulation 4,48% 0,09% 5,74% 7,82% 7,64% 7,17% 7,86% 10,62% 11,21% 36,21% MAPE
9,88%
Aerodynamics Performance of NACA 2412 Using Flap and Slat Figure 5 shows the CL and CD values change for the flap deflection at the Angle of Attack 0o.
The flap deflection varies from the state of the flap closed to 0A, 10A, 15A, 20A, 25A, 30A, 35A, 40A, 45A, 50A, 55A, 60A.
Each increase in the flap deflection increases the value of the lift coefficient until the maximum value at the optimal flap opening, then decreases the value of the lift coefficient after reaching the highest point of its ability, namely at 40A flap deflection .
The value of the drag coefficient continues to increase as the flap opening increases without decreasing with each increase in flap opening.
The state taking that will be discussed is in the form of 30A and 40A flap deflection by considering the efficient SJME KINEMATIKA Vol.
10 No.
2, 14 Oktober 2025, pp 265-276 https://kinematika.
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php/kinematika CL and CD values for takeoff and landing conditions which are then compared between the CL and CD Flap Angle Figure 5.
CL and CD values at various flap deflection at angle of attack of 0o Figure 6.
The contours of the NACA 2412 airfoil pressure with a flap configuration of deflection 30A and 40A at an angle of attack of 0A Figure 6 shows the contours of the NACA 2412 airfoil pressure with a flap configuration of 40A at an angle of attack of 0A.
The flap opening causes a change in the camber of the airfoil so that the pressure under the airfoil increases significantly at the 40A flap has a maximum pressure of 208.
359 Pa.
The pressure on the NACA 2412 airfoil occurs at a certain point with a different amount of pressure and at each point, as seen in the picture Greater pressure occurs on the front of the airfoil and flap because the flow slows down at points of curvature and changes direction so that the pressure in that area is greater than in other parts.
Angle of Attack Normal Airfoil Slat Flap 30A Slat Flap 40A Slat Figure 7.
CL of normal NACA 2412 airfoils, with flap and slat configurations SJME KINEMATIKA Vol.
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php/kinematika Normal Angle of Attack Airfoil Slat Flap 30A Slat Flap 40A Slat Figure 8.
CD of normal NACA 2412 airfoils, with flap, and slat configurations To increase the angle of attack in takeoff and landing conditions, adding a slat configuration on the NACA 2412 leading edge airfoil when the flap is closed, the flap deflection is 30A, and the flap deflection is 40A.
Figures 7 and 8 show a comparison of CL and CD values between normal NACA 2412 airfoils, additional flaps, and flap and slat Figure 7 shows that the lift coefficient with the additional slat configuration using 30A and 40A flap deflection significantly changes from the airfoil force coefficient with the slat configuration without the flap and it reached a maximum angle of attack of 24A.
low angles of attack, the slat does not affect the CL value of the NACA 2412 airfoil.
On the other hand, the CD value is higher at a low angle of attack and lower at a high angle of attack compared to a standard airfoil, as shown in Figure 8.
Figure 9.
NACA 2412 airfoil streamline without slat at the angle of attack 22A Figure 10.
NACA 2412 airfoil streamline with slat at the angle of attack 22A SJME KINEMATIKA Vol.
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php/kinematika Figure 9 shows that there is air separation at the top of the airfoil after the airfoil breaks up the airflow.
This is because the air cannot follow the shape of the airfoil surface at a high angle of attack.
Adding a slat reduces the air separation in the NACA 2412 airfoil, as seen in Figure 10, where the air separation is reduced to half above the airfoil.
With the addition of the slats, the angle of attack of the NACA 2412 airfoil is increased by 6A.
The use of slats is one of the aerodynamic techniques for STOL aircraft.
Slat is one of the tools that can increase lift by controlling the boundary layer on the aircraft wing.
The added slat has a slot or distance between the slat and the airfoil.
High-pressure air at the bottom of the airfoil flows to the top of the airfoil through the gap then the airflow is directed by the slat and controls the boundary layer to delay or reduce the air separation at the top of the airfoil.
Furthermore, it can be seen that slat significantly influences a high angle of attack.
At a low angle of attack, the CL value decreases when a slat is added compared to an airfoil without a slat, but at a high angle of attack, the slat can maintain the value C L to exceed the normal airfoil CLmax value.
CLmax increases greatly, and the stall is delayed by a large number of angles of attack.
when the slat is applied to the airfoil with 30A and 40A flap Figure 11.
NACA 2412 airfoil streamline with deflection flap 30o and slat at the angle of attack 24A The application of slats at 30A and 40A flap deflection in takeoff and landing situations at low speed of 20 m/s with an angle of attack of 24A compared to the configuration without slats can be seen from the flow pattern that occurs.
The flap deflection configuration of 30A at an angle of attack of 24A shows that the air separation occurs wider at the top of the airfoil.
When the slat is added, the air separation can be damped, affecting the airflow velocity around the airfoil, as seen in Figure 11.
Therefore, the slat is very influential at a high angle of attack to prevent early stalls.
By using slats, an increase in the angle of attack occurs when slats are applied to the aircraft wing.
Therefore, additional flap and slat configurations on NACA 2412 airfoil affect the effective chord line and camber, resulting in significant increases in CL.
CD, and stall angle values.
The increase in camber affects the wing surface area, which increases the wing area and allows it to operate at low speeds.
Figure 12 shows the CL/CD value generated by the airfoil at each angle of attack of normal NACA 2412 airfoils, with flap and slat configurations.
The Figure shows that the 30A flap deflection is more efficient than a 40A flap deflection with the addition of a slat configuration.
This is due to the increased lift combined with low drag and minimal flow separation at a 30A flap deflection.
The air separation in the 40A flap deflection is greater than the 30A flap deflection, both before and after the slat configuration addition, as seen in Figures 13 and 14.
The difference between the two flap deflections is the separation at the back of the flap.
The total separation at 40A flap deflection is greater than at 30A flap deflection, which causes a difference in the SJME KINEMATIKA Vol.
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php/kinematika maximum lift coefficient between the two at the same angle of attack.
This becomes the advantages and disadvantages of each configuration that can be adapted to the needs and use of STOL aircraft.
CL/CD
Angle of Attack Normal Airfoil Slat Flap 30A Slat Flap 40A Slat Figure 12.
CL/CD of normal NACA 2412 airfoils with flap and slat configurations Figure 13.
Contour velocity of the deflection flap 30A with an additional slat at angle of attack of Figure 14.
Contour velocity of the deflection flap 40A with an additional slat at angle of attack of CONCLUSION The results of the CFD simulation using the Ansys Academic Student 2022 R2 software on the aerodynamic characteristics of the NACA 2412 airfoil with additional flap and slat configurations can be concluded:
SJME KINEMATIKA Vol.
10 No.
2, 14 Oktober 2025, pp 265-276 https://kinematika.
id/index.
php/kinematika Each increase in the flap deflection increased the value of the lift coefficient until the maximum value at the optimal flap opening, then decreased the value of the lift coefficient after reaching the highest point of its ability, namely at 40A flap deflection.
The application of the slat configuration can delay air separation.
In the NACA 2412 airfoil without a slat with an angle of attack of 22A, the separation point occurred earlier at the front of the airfoil, with the additional slat separation point shifting backward in the middle of the airfoil.
At low angle of attack, the slat did not increase the CL value but provided additional drag on the NACA 2412 airfoil.
Adding flap and slat configurations on NACA 2412 airfoil affected the airfoil's camber and effective chord line, which caused a significant raise in the CL.
CD, and stall angle values and reached a maximum angle of attack of 24A.
The increase in camber affected the wing surface area, where the wing area increased so that it can operated at low From the results of a comparison between 30A and 40A flap deflection with slat addition, as seen from the maximum lift coefficient and CL/CD ratio, it is known that a 30A flap deflection is more efficient than a 40A flap deflection in takeoff conditions.
The average percentage increased from 30A to 40A flap was 17.
ACKNOWLEDGMENT
The authors would like to express special gratitude to the Adisutjipto Institut of Aerospace Technology (ITD Adisutjipt.
for the funding incentives for this research
REFERENCES