Caner ATLI’s Post

Knudsen number Kn🤔 Fluids consists of particles, though the famous Navier-Stokes equations treat fluids as continuum. If you get higher and higher in altitude air density drops and air particles become apart. Now, particles are less likely to collide. This is what Knudsen number tells us 💡 It relates particals meen free path to object characteristic length. 🟢For Kn < 0.01, the flow can be considered continuum which can be said about most of engineering flows. 🟠For 0.01 < Kn < 0.1, Navier-Stokes equations can be applied but the no-slip boundary condition doesn’t hold any more, so it is called slip flow. 🟡For 0.1 < Kn < 10, the flow is in a transitional region to the free molecular flow (Kn > 10). Now, molecular based schems should be used such as Boltzmann transport equation BTE or Direct simulation Monte Carlo DSMC. The chart represents Knudsen number in US76 standard atmosphere model for a 1m characteristic length body. Retrieved from: https://lnkd.in/dJPNZGSb #aerodynamics #aerospace #CFD

Excited to share this simulation demonstrating the flow around a NACA 0012 airfoil at a 25-degree angle of attack. The video compares three turbulence models—DDES, URANS, and RANS—highlighting the differences in their simulation results. A great example of how advanced CFD tools can enhance our understanding of complex aerodynamic phenomena. Source: https://lnkd.in/dVHcAktR #CFD #Aerodynamics #TurbulenceModels

A testing purpose of H3 hypersonic wind tunnel of von Karman Institute for Fluid Dynamics is to do measurements of low temperature ablation phenomenon. The unique long duration testing capabilities of the facility allows stable hypersonic conditions for characterizing aerothermochemistry of  thermal protection system (TPS) materials for cruise vehicles and re-entry capsules. Here is one of the first productive tests we have performed after commissioning the new Mach 5 nozzle with Andrea Perin and David Henneaux using wax, gallium and polylactic acid models for validation of numerical simulations. #aerodynamics #hypersonic #schlieren #reentry #aerospace #thermalprotectivesystem #ablation

For hypersonic simulations, flow solvers typically have challenges predicting surface heat fluxes when strong shocks are present, the new process shown in this week’s #tutorialtuesday video enables users to quickly create grids for accurate heating estimates for a complex geometry. This method offers the advantage of speed and accuracy that the #structured #meshes have and offers the flexibility of unstructured meshes. One of the main highlights is the cripser capture of the shock since you have highly orthogonal cells along the initial shock region. YouTube Video - https://hubs.ly/Q02GKh4P0 #CFD #ComputationalFluidDynamics #aerodynamics #aerospace #ShockWave #Hypersonic #Supersonic #FluidDynamics #flowcontrol

✈️ FDTD Simulation of a Moving MiG Jet Plane 🌌 Here’s a glimpse into my latest FDTD simulation, where a MiG jet is illuminated by a plane wave, showcasing the dynamic interaction of electromagnetic waves with the aircraft in motion. This simulation provides intriguing insights into wave behavior in complex scenarios. 🎓 This research is proudly funded by Fonds de recherche du Québec. What potential applications do you see for such simulations? Let’s discuss! 💡 #FDTD #ElectromagneticSimulation #RadarTechnology #MiGJet #AerospaceEngineering #NumericalMethods #ComputationalPhysics

Numerical simulation of airflow around the NACA2312 airfoil profile in supersonic regime

Cool video showcasing FSI in action—watch how the opening of a dam gate influences water flow and how the diaphragm deforms under the fluid forces. The video highlights the importance of integrating FSI into CFD for more accurate real-world predictions. Courtesy of the magnificent Mohamed Aly Sayed (with his permission). Definitely subscribe to his CFD Dose newsletter: https://lnkd.in/dWqHQE9n #cfd #engineering #aerodynamics #aerospace #mechanicalengineering

Rotor dynamics Simulation...

In our newest publication "Improving PPP positioning and troposphere estimates using an azimuth‑dependent weighting scheme" (open access: https://lnkd.in/e5z7qujb) He et al. show that this novel stochastic model has the potential to significantly improve PPP estimation (approximately 10% in the horizontal and 20% in the vertical direction in terms of station position repeatability). Give it a try in your PPP software and let us know if you need any help in implementing the model. #PPP #GNSS #troposphere #stochastic #model #weighting #improvement Aerospace Engineering and Geodesy | University of Stuttgart University of Stuttgart Spirent Positioning, Navigation, and Timing

Excited to be working on high-speed small craft propelled by waterjets! 🚤💨 Waterjet propulsion presents unique challenges, especially given the relatively limited literature compared to traditional propellers. Using the multiphase CFD solver CFDShip-Iowa V5.5, we're accurately modeling the free-surface interface at high speeds (Fr=2.0, as shown in the attached video). Our current model is based on a 12.88m GPPH craft, with a body-force model simulating the pump action. Next steps? Implementing nozzle steering capabilities and running maneuvering simulations to compare the craft performance with outboard propellers. 🌊 #CFD #Waterjets #NavalEngineering #Innovation