A Diverterless Supersonic Intake of Aircraft CFD simulation is a computer model of a special air inlet for modern jets. This advanced design, called a DSI, is used on Stealth Aircraft because it is simpler and harder to see on radar. A Diverterless Supersonic Intake of Aircraft Fluent simulation is very important for engineers. It helps them study how the intake performs at very high speeds. The main job of the intake is to slow down the fast supersonic air before it goes into the jet engine. This analysis, called a Compressible Flow Simulation, looks at complex things like shock wave management and pressure recovery. By understanding these, we can design an intake that gives the engine the best quality air with low engine face distortion, which helps the aircraft fly efficiently. For comprehensive aerodynamics and aerospace CFD simulations, explore our extensive collection at CFDLAND Aerodynamics Simulations.

• Reference [1]: Svensson, Marlene. A CFD investigation of a generic bump and its application to a diverterless supersonic inlet. 2008.

Figure 1: A 3D model of the Diverterless Supersonic Intake (DSI), showing the characteristic bump feature

Simulation Process: Fluent Setup, 3D Compressible Flow Modeling with Symmetry

To perform this Diverterless Aircraft CFD study, a 3D model of the intake was used. Because the DSI geometry is perfectly symmetrical, we used a very smart and efficient technique in ANSYS Fluent. We applied a symmetry boundary condition, which allowed us to model only half of the intake. This saves a very large amount of computer calculation time but still gives a completely accurate result for the entire system.

The simulation was set up to model the aircraft flying at supersonic speed. A pressure far-field boundary condition was used for the air surrounding the aircraft, with the speed set to Mach 1.6. Inside ANSYS Fluent, it is to consider compressibility essential because at supersonic speeds, the density and temperature of the air change a lot. This accurately calculates the physics of high-speed flight, including the formation of shock waves, expansion fans, and the large changes in pressure and temperature that happen as the air flows through the intake.

Post-processing: CFD-Post Analysis, Investigating Intake Performance, Flow Deceleration, and Structural Loads

The simulation results provide a complete engineering validation of the DSI’s design, proving that it can effectively manage supersonic airflow without complex moving parts. The pressure contours in Figure 2 show the first and most important job of the intake: compressing the air. We can see high-pressure zones forming at the nose and on the special “bump” of the intake. These are caused by shock waves, which are created by the DSI’s shape to slow the air down. The pressure rises from a low of -8.07e+04 Pa to a maximum of 1.60e+05 Pa at the intake throat. This high pressure is direct proof that the intake is successfully compressing the air, a process known as pressure recovery. This is the first step in preparing the air for the engine.

Figure 2: Pressure Distribution Around Diverterless Supersonic Intake at Mach 1.6

The velocity contours in Figure 3 show the direct result of this pressure rise. The freestream air approaches the aircraft at a high velocity of 510 m/s (Mach 1.6). As the air flows through the shock waves created by the bump, it slows down significantly. The contours clearly show the air decelerating smoothly from high-speed supersonic flow to much slower subsonic flow inside the intake duct. The key achievement shown here is the successful and smooth deceleration of the flow to subsonic speeds before it reaches the engine, which is the primary function of any supersonic intake.

Figure 3: Velocity Field Distribution Showing Supersonic Flow Deceleration

This process of slowing down fast-moving air creates large forces on the structure, as shown in Figure 4. The analysis quantifies these forces, showing a maximum force of 108 N on the intake walls. The contours pinpoint exactly where these high forces occur: on the DSI bump and at the intake throat. This is critical information for structural engineers. It tells them where the intake needs to be strongest to operate safely. It also shows areas with low forces, where it might be possible to reduce weight.

The most important achievement of this simulation is the successful study of the diverterless intake concept. The CFD model proves that the simple, fixed geometry of the DSI can effectively use shock waves to slow down Mach 1.6 air and generate the high pressure recovery needed for engine operation. It provides the critical pressure, velocity, and force data needed to confirm the aerodynamic performance and structural integrity of the design.

Figure 4: Force Distribution on Diverterless Intake Structure