Pimentel's blog

Once the International Searching Authority (ISA) of the United States Patent and Trademark Office (USPTO) has determined that my international patent application "Full-surface detached vorticity method and system for solving fluid dynamics" (WO/2024/136634) , under the Patent Cooperation Treaty (PCT), meets all three criteria for patentability ( novelty, inventive step, and industrial applicability ), it will be time to make an open offer to exploit such an invention (in the prosecution phase) through a Patent Licensing Agreement (PLA). Fig. 1 The generation of vorticity on surfaces is a purely inviscid mechanism (Morton, 1984, and Terrington et al., 2022). This time I will not write about the technical aspects of the patent (or how wonderful it is! ), since I did that in a previous post:  More patents, less papers (librepenzzzador.blogspot.com) . Now, I want to focus on my business proposal. Since I have some experience as an entrepreneur in engineering ( www. chuteshiut...

The dynamics of a separated fluid flowing past an object is still a challenging problem in engineering, even in low-speed aerodynamics, where turbulence can be present, making its understanding and solution more difficult. For this reason, some numerical methods have been developed, most of them based on the Eulerian description of the Navier-Stokes equations, by measuring the fluid-flow variables at fixed points defined by a continuous spatial mesh, which in most cases includes several assumptions and empirically based models, to approximate (and artificially close ) the governing equations. In the first place, such methods are relatively computationally expensive, since they calculate the variables in the entire surrounding space, even far away from the object, where their measurement is of little value. Fig. 1 Mesh-based CFD simulation of a parabolic parachute canopy by κ-ω SST turbulence model (Pimentel, 2016). For several decades, the Boundary Element Method (BEM; e.g., panel ...

This list is a summary of misinterpretations that I have noticed during the last years as an aeronautical engineer, which from my perspective (and probably in the opinion of the editors and reviewers who have understood and published my research) do not allow to know the fundamental physics of real aerodynamics (and fluid dynamics). As usual in this blog, I try to be concise by explaining each of them in a single paragraph. No more blah, blah, blah, and let's get to the point. Fig. 1 Continuity exists everywhere. Sky and Water (M.C. Escher, 1938). 1. "Ideal flows perfectly attach to the surfaces". Although it is not yet possible to confirm or deny this from an experimental point of view ( the superfluid fountain is not a flow past an object experiment), the Potential Flow Theory (PFT) assumes that an ideal (i.e. incompressible, irrotational, and inviscid; i-i-i) flow will turn around, even with sharp leading edges, to maintain a perfectly attached flow pattern to the bo...

In the context of high Reynolds number aerodynamics, what does it mean to have a "laminar boundary layer" (BL)? How long is it on a wing under normal operating conditions? According to Reynolds number calculations, at best it can be no longer than a few centimeters from the leading edge! (see Fig. 1). So can we talk about a laminar BL in both the physical transition and turbulent regimes, including their instabilities and vortices ? What about so-called "laminar airfoils" ? Perhaps most of the aerodynamicists (experimentalists, theorists, and computationalists) are abusing on oversimplifying things to make everything fit with their own interpretations? Fig. 1 Surface oil flow visualization of a wing upper surface (AR=3, AoA=0 deg., Re=1E6). The fluid separation region (transition to turbulent BL; ignore the red rectangle) is clearly marked around the top of the wing.  Source: "Variable Camber Compliant Wing-Wind Tunnel Testing", C.R. Marks et al. (2015)...

Eddies, vortices, whirlpools, tornadoes, and hurricanes; all of these fluidic structures have the same thing in common: they all rotate around a point by a vectorial quantity (which may vary with time). This is where the term "vorticity" comes in. Mathematically, vorticity is defined as the curl of the velocity : 𝜔 ( r , t)=∇× 𝑢 ( r , t). Since the velocity field depends on its position ( r ) and time (t), vorticity also does. Then, vorticity within a vortex can be explained as a measure of the rotation of a flow element as it moves along a closed (circular) streamline about an axis, maintaining a circumferential translation. In an ideal (incompressible, irrotational, and inviscid) vortex, all flow elements remain without local rotation, where they are still irrotational   ( 𝜔 =0 everywhere, except along the axis). Fig. 1 Spiral vorticity. Unlike solid-body rotation, the tangential velocity decreases with increasing distance from the vortex center. Source: https://64.media...

Recently, my second journal article in the series ( The Unsteady Full Multi-wake Vortex Lattice Method: a full rolled-up detached vorticity approach [1]) was declined for publication four months after its acceptance (already peer-reviewed) in a second quartile (Q2) journal. This is not due to a lack of consistency in methodology or results, but due to lack of payment of the Article Processing Charge (APC)!, which neither the university nor the Science Council 'can' afford, although both of them are included in the remaining two articles, published without APC in a Q1 journal. Fortunately, I have never been interested in becoming a  paper-publishing researcher  to try to play the game imposed by the current academic system; I have only published my research as a requirement to obtain my PhD degree. However, this does not mean that I believe that knowledge should be restricted; ideally, the knowledge should be open and universal, especially when it concerns the foundations of a ...

There is a classic figure shown in theory of flight  (for pilots) and aerodynamics and flight mechanics subjects (for aeronautical engineering students) that shows a free body diagram with four "forces" acting on an airplane: weight (W), thrust (T), lift (L), and drag (D). Even the NASA Glenn Research Center website shows it: Fig. 1 Retrieved from:  What is Lift? | Glenn Research Center | NASA NASA begins by answering the question, "What is lift?" :  "Lift is the force that directly opposes the weight of an airplane and holds the airplane in the air...Lift is a  mechanical aerodynamic force  produced by the motion of the airplane through the air" . But are lift and drag really forces? Or are they just the perpendicular and parallel projections of a resulting force vector? I am pretty sure that all aerodynamicists at NASA know the correct answer. Presenting it in this way is indeed easier to explain to kids and aeronautics novices, however, such express...