Simulation of Airflow Patterns and Aerodynamic Forces on a Chambered Airfoil and Symmetric Airfoil with Maximum Thickness Variation

Flow across the airfoil can cause drag and lift forces. The difference in pressure between the top and bottom surfaces of the airfoil creates a force that is perpendicular to the flow of fluid, and this force is called the lift force, and parallel to the flow is called the drag force. The author conducted research on simulating airflow patterns across the airfoil with maximum thickness variations. In this research, the simulation method is CFD (Computational Fluid Dynamic) using ANSYS Fluent software. The solution or solver method used in this simulation is the SIMPLE (Semi Implicit Method for Pressure Linked Equation) scheme. The flow pattern is shown by the streamline formed on the symmetric airfoil for α=0°, which will be symmetric, as well as the separation on the two sides, both the upper and lower sides. In contrast to the chambered airfoil, flow separation occurs only on the upper side. This indicates that there will be a pressure difference on the upper side and lower side so that the lift force can occur even though α=0°, because the lower side shows the pressure side. The greater the maximum thickness, the faster flow separation occurs. Then the higher the velocity value, the flow separation will be delayed due to an increase in the momentum of the working fluid flow, which overcomes the shear stress that occurs. At the angle of attack α=0°, the greater the maximum thickness of the chambered airfoil produces a greater lift force, while the symmetric airfoil does not produce lift.


A B S T R A C T
Flow across the airfoil can cause drag and lift forces. The difference in pressure between the top and bottom surfaces of the airfoil creates a force that is perpendicular to the flow of fluid, and this force is called the lift force, and parallel to the flow is called the drag force. The author conducted research on simulating airflow patterns across the airfoil with maximum thickness variations. In this research, the simulation method is CFD (Computational Fluid Dynamic) using ANSYS Fluent software. The solution or solver method used in this simulation is the SIMPLE (Semi Implicit Method for Pressure Linked Equation) scheme. The flow pattern is shown by the streamline formed on the symmetric airfoil for α=0°, which will be symmetric, as well as the separation on the two sides, both the upper and lower sides. In contrast to the chambered airfoil, flow separation occurs only on the upper side. This indicates that there will be a pressure difference on the upper side and lower side so that the lift force can occur even though α=0°, because the lower side shows the pressure side. The greater the maximum thickness, the faster flow separation occurs. Then the higher the velocity value, the flow separation will be delayed due to an increase in the momentum of the working fluid flow, which overcomes the shear stress that occurs. At the angle of attack α=0°, the greater the maximum thickness of the chambered airfoil produces a greater lift force, while the symmetric airfoil does not produce lift.

Natural Sciences Engineering & Technology Journal (NASET Journal)
flow, the friction that will determine the physical state of the flow. Reynolds number is generally used to state that viscosity has an important role in determining the type/type of flow of a fluid. Furthermore, the flowing viscous fluid will form a boundary layer on the solid surface. This boundary layer becomes a hypothetical boundary which is the area of the dominant fluid viscosity effect and the area that can be considered an inviscid (non-viscous) region hypothetically. [7][8][9][10] External flow across the interfering body will affect the flow phenomena that occur from the flow, such as the formation of wakes and drag forces caused by flow separation. Separation is indicated when the momentum of the working fluid upstream (upstream) is no longer able to overcome the shear stress that arises. As a result, the downstream momentum (downstream) will push a smaller momentum (upstream direction), and the flow will move in the opposite direction (towards the upstream). The phenomenon of This flow is called backflow/adverse pressure gradient occurs. [11][12][13] Flow across the airfoil can cause drag and lift forces. The magnitude of the drag and lift forces is influenced by parameters, namely: coefficient of force, Flow Velocity, and outward flow projection. The coefficient of drag force and lift force is strongly influenced by the dimensions of the airfoil. Thus, the dimensions of the airfoil can affect the drag force and lift force that occurs. 14 An airfoil is a form of aerodynamics intended to produce a large lift with the smallest possible drag.
When an airfoil is passed by a fluid flow, the interaction between the airflow and the surface will cause variations in Velocity and pressure along the top and bottom surfaces of the airfoil as well as at the front and back of the airfoil. The difference in pressure between the top and bottom surfaces of the airfoil will cause a resultant force whose direction is perpendicular to the direction of the fluid flow, and this force is referred to as lift. The size of the lift that occurs will vary depending on the geometry of the airfoil and its operating conditions. 15,16 This study aims to simulate airflow patterns and aerodynamic forces on a chambered and symmetric airfoil with maximum thickness variation.

Methods
The research was conducted using the CFD

Results and Discussion
The flow pattern of airfoil a with a speed of 80 m/s        In symmetric airfoils, the style of the elevator will eliminae each other on the upper side and lower side.
In contrast, the drag force will increase with the increasing speed and contact area of the working fluid, = 1 2 . . 2 . . means that the greater the maximum thickness, the greater the contact area.

Conclusion
The greater the maximum thickness, the faster the flow separation occurs. The flow pattern is indicated by the streamline that is formed on the symmetric airfoil for α = 0°, which will be symmetric a well as the