Detonation phenomena in reactive flow systems continue to pose significant challenges for accurate simulation, particularly in 3D validation against experiments and achieving community standardization for schemes. Among the primary difficulties is the selection of suitable convective schemes, which are essential for capturing the complex dynamics of wave propagation and reaction fronts. This study provides a comprehensive historical review of the development and implementation of convective schemes in OpenFOAM, covering the period from 2013 to the present. In addition to documenting the evolution of these methods, we present a detailed technical description of various convective approximation techniques used in detonation simulations within OpenFOAM. This includes an exploration of their underlying principles, advantages, and limitations. Our analysis synthesizes key findings from recent studies and offers practical guidance to researchers when choosing schemes for specific detonation scenarios. It is found that currently, within OpenFOAM, the dominant schemes for convection are the HLLC and KN.

This study focuses on the numerical analysis of the interaction between the exit flows of two supersonic nozzles, using the distance between their longitudinal axes as a parameter. The analysis is conducted in OpenFOAM, assuming two-dimensional, inviscid flow. The methodology employed to simulate flow in a nozzle is validated against experimental data and is subsequently used to investigate the interaction with a second nozzle. The numerical results indicate that discharge flows interfere, even from distant nozzles.

On November 14, 2025, a large-scale explosion at the Ezeiza Industrial Pole (Argentina) generated a blast wave that propagated through a dense industrial layout, causing extensive structural damage. This study presents a three-dimensional Computational Fluid Dynamics reconstruction of the event using the rhoCentralFoam solver within the OpenFOAM framework, implementing the Kurganov-Noelle-Petrova central-upwind scheme. Given the limited forensic evidence available, a single video recording of the event, the initial energy release was estimated through a multi-model approach combining video-derived time-of-arrival data with independent empirical scaling laws, and subsequently calibrated to 0.022 kt of TNT equivalent by comparing computed incident and reflected overpressures against documented structural damage thresholds. Modeling the explosion as an instantaneous energy release, rather than resolving detailed chemical kinetics, allowed the simulation to capture intricate wave-structure interactions, including reflection, diffraction, and shock refocusing, at reduced computational cost. Results show that the resulting blast loading is governed less by stand-off distance than by the local wave-structure interaction, with upstream shielding, corridor channeling, and refocusing effects redistributing the load in ways a distance-based estimate would not predict. The temporal asymmetry of the loading observed across elongated facades, arising from the progressive sweep of the shock front, offers a plausible physical explanation for the severe structural twisting documented in forensic reports.

In this current study, we developed a second-order Kurganov–Tadmor scheme in curvilinear coordinates to analyze the external supersonic flow over bodies of various shapes. This scheme is capable of handling interfaces across different regions of the domain. We utilized a fourth-order Runge–Kutta temporal integrator and conducted several test cases to validate the performance of the new scheme. The results from the analyzed tests indicate that the new method produces highly accurate outcomes.

Las fallas en tanques atmosféricos son un problema crítico en la industria petrolera, frecuentemente causadas por sobrepresiones debido a su vulnerabilidad estructural. Aunque raramente provocan lesiones, generan importantes pérdidas materiales e interrupciones operativas. Este trabajo analiza la interacción entre ondas de explosión y tanques, enfocándose en el efecto de la altura de detonación. Mediante simulaciones con rhoCentralFoam en OpenFOAM, se modelaron explosiones esféricas a diferentes alturas (distancia horizontal constante), considerando la energía liberada como puntual/lineal e instantánea. Se omitieron reacciones químicas para eficiencia computacional, usando aire como único fluido. Los resultados muestran que explosiones elevadas producen dinámicas complejas (ej. formación de pierna de Mach) y sobrepresiones localizadas, revelando limitaciones en los métodos de diseño actuales. El estudio provee bases para mejorar normas de seguridad y estrategias de refuerzo estructural, ofreciendo una metodología innovadora para analizar interacciones explosión-estructura en la industria.

Este trabajo valida el uso del esquema numérico Kurganov-Noelle-Petrova (KNP) en el solver rhoCentralFoam de OpenFOAM para simular ondas de explosión y su interacción con tanques de almacenamiento. El modelo emplea una aproximación simplificada de liberación instantánea de energía en geometrías esféricas o cilíndricas, prescindiendo de reacciones químicas y considerando solo aire. Esta simplificación ofrece grandes ventajas computacionales, reduciendo la complejidad numérica mientras mantiene la precisión en los parámetros clave de la onda de choque. La validación se realizó comparando los resultados con soluciones analíticas (teoría de Sedov), directrices empíricas y datos experimentales. Los resultados demuestran que el esquema captura con alta precisión las sobrepresiones (error < 10%), los tiempos de llegada (error < 5%) y fenómenos complejos como las reflexiones de Mach. El estudio confirma que el método KNP es una herramienta robusta y fiable para el análisis de riesgos y evaluaciones de seguridad en instalaciones industriales, destacando la crucial importancia de considerar los efectos tridimensionales para mejorar los estándares de protección.

To explore intermittency in discrete systems with two or more degrees of freedom, we analyze the general characteristics of type I intermittency within a two-dimensional map. This investigation is carried out numerically, concentrating on the system’s attractors, bifurcation diagrams, and the characteristic relation associated with type I intermittency. We present two methods for determining the laminar interval and the channel structure. Our computations yield numerical results for the average laminar length as a function of the control parameter, which we then compare with findings from intermittency in one-dimensional maps. We observe a strong agreement between the numerical data and the theoretical predictions.

Reliable simulations of any flow require proper preservation of the fundamental principles governing the mechanics of its motion, whether in differential or integral form. When these principles are solved in differential form, discretization schemes introduce errors by transforming the continuous physical domain into a discrete representation that only approximates it. This paper analyzes the numerical performance of the solver for supersonic chemically active flows, rhoCentralRfFoam, using integral conservation principles of mass, momentum, energy, and chemical species as a validation tool in a classical test case with a highly refined mesh under nonlinear pre-established reference conditions. The analysis is conducted on this specific test case; however, the methodology presented here can be applied to any problem under study. It may serve as an a posteriori verification tool or be integrated into the solver’s workflow, enabling automatic verification of conservation at each time step. The resulting deviations are evaluated, and it is observed that the numerical errors remain below 0.25%, even in cases with a high degree of nonlinearity. These results provide preliminary validation of the solver’s accuracy, as well as its ability to capture physically consistent solutions using only information generated internally by the solver for validation. This represents a significant advantage over validation methods that require external comparison with reference solutions, numerical benchmarks, or exact solutions.

A wide range of processes can be characterized by a random telegraphic signal, which is essentially a time-dependent signal that oscillates randomly between two distinct values. Meanwhile, the concept of chaotic intermittency holds significant relevance across various fields, including physics, engineering, and medicine, among others. This paper aims to establish a connection between these two topics to deepen our understanding of chaotic intermittency. Specifically, we explore how the probabilities associated with waiting or sojourn times in random telegraphic signals can be linked to the probability density of laminar lengths, as determined through a novel theoretical framework of chaotic intermittency. To validate our theoretical findings, we conduct a series of numerical experiments focused on three different types of intermittencies: type I, type II, and type III. We demonstrate that the correlation between random telegraphic signals and chaotic intermittency offers several advantages. In particular, this formulation enables the evaluation of the probability that the system remains in either a laminar or chaotic phase. Therefore, this technique facilitates the comparison between analytical and numerical approaches, and we conclude that there is a very close alignment between both approaches.

El solucionador rhoCentralRfFoam, basado en rhoCentralFoam (OpenFOAM), está diseñado para resolver las ecuaciones de Euler para flujos compresibles químicamente reactivos con modelos de reacción detallados. A diferencia del solver base, este incorpora la resolución de las ecuaciones de transporte de las especies químicas. Al emplear una formulación central-upwind explícita, la definición del flujo numérico en dichas ecuaciones resulta crítica, ya que condiciona directamente la estabilidad y precisión de las soluciones. En este trabajo se analizan dos estrategias para su cálculo: (i) la multiplicación del flujo volumétrico por la variable conservada (rhoY), tratada como una única magnitud, y (ii) la multiplicación del flujo volumétrico por las variables primitivas correspondientes, la densidad (rho) y la fracción másica (Y), consideradas por separado. El objetivo de este trabajo es evaluar el impacto de ambas formulaciones sobre la estabilidad y consistencia física de las soluciones, con el fin de identificar el enfoque más preciso y estable.

Turbulent flows play a crucial role in various engineering and scientific applications, and the accurate prediction of these flows remains a challenging task. This review explores the application of the Shear Stress Transport Scale-Adaptive Simulation (SST-SAS) turbulence model for solving incompressible turbulent flows, with a specific focus on unsteady wakes behind bluff bodies. Providing a concise overview of the model’s formulation and its advantages, this article highlights the efficacy of the SST-SAS model in simulating the intricate dynamics in different configurations of circular cylinders. The present study affirms that the SST-SAS model can be considered a highly viable alternative for simulating unsteady flows around bluff bodies due to the good predictive quality of the resulting simulations.

The shock wave generated by the instantaneous release of energy in the centre of a closed domain, its subsequent rebound and reflections are studied in this article. Three cases are simulated where the Mach number of the wave is Ms = 2, 5 and 10. As a result of the interactions between a low-density central zone and the shock waves, the Ritchmyer-Meshkov instability is produced, which is manifested by the breaking of the flow symmetry. The results of the simulations are compared with those presented in previously published works (starting point of the symmetry breaking and the reflected pressures on the walls). The Euler equations are solved using the Kurganov, Noelle and Petrova (KNP) scheme with the rhoCentralFoam solver of the OpenFOAM software, due to the fact that in previous works it has been shown to be able to study with adequate accuracy the representation of wave reflection phenomena on straight walls.

The paper studies the influence of the Minmod, van Leer and van Albada flux limiters to numerically simulate the formation of a blast wave following an instantaneous energy release. Mesh and CFL sensitivity analyses are carried out using the upwind reconstruction and the Minmod limiter. Important differences are found in the time step sensitivity analysis between the upwind scheme and when a limiter is implemented, where a lower CFL is necessary to properly describe the flow field. Different comparisons of pressure, velocity, temperature and density profiles between the upwind reconstruction and the Minmod, van Leer and van Albada limiters are studied for different times after energy release. It was found that the upwind scheme is highly diffusive due to the nature of the scheme itself and cannot correctly capture some discontinuities. The simulations are carried out using the Kurganov, Noelle and Petrova (KNP) scheme in the rhoCentralFoam solver implemented in the OpenFOAM software.

Many physical processes feature random telegraph signals, e.g., a time signal c(t) that randomly switches between two values over time. The present study focuses on the class of telegraphic processes for which the transition rates are formulated by using fractal-like expressions. By considering various restrictive hypotheses regarding the statistics of the waiting times, the present analysis provides the corresponding expressions of the unconditional and conditional probabilities, the mean waiting times, the mean phase duration, the autocorrelation function and the associated integral time scale, the spectral density, and the mean switching frequency. To assess the relevance of the various hypotheses, synthetically generated signals were constructed and used as references to evaluate the predictive quality of the theoretically derived expressions. The best predictions were obtained by considering that the waiting times probability density functions were Dirac peaks centered on the corresponding mean values.

In this article we present a method for calculating the thermomechanical conditions behind a normal and stationary shock wave in both calorically perfect and calorically imperfect (or thermally perfect) gases. In both cases the ideal gas equation of state is satisfied, but in the latter the specific heats vary nonlinearly with temperature. In addition, we evaluate the main differences when applying the Rankine-Hugoniot conditions to air under the assumptions of a calorically perfect and imperfect gas, with the aim of determining whether there are significant differences that would justify the use of one constitutive model over the other.

In this paper we study the wave structure by an instantaneous release of energy from which a blast wave is formed. The aim is to describe and understand the wave structures in one dimension after a near-instantaneous energy release. Numerical simulations were carried out with the OpenFOAM rhoCentralFoam solver using the Kurganov, Noelle and Petrova scheme. Mesh and CFL sensitivity analyses were performed, where the need for very low CFL values is observed to avoid the presence of spurious oscillations. Different pressure, velocity, temperature and density profiles are studied and described for different times after energy release. It was also observed that there are no differences in using the first order upwind scheme or the TVD Minmod limiter. Finally, the wave structures are compared if the classical shock tube or a blast tube is used, varying the boundary conditions of the simulations.

One-dimensional maps showing chaotic intermittency with discontinuous reinjection probability density functions are studied. For these maps, the reinjection mechanism possesses two different processes. The M function methodology is applied to analyze the complete reinjection mechanism and to determine the discontinuous reinjection probability density function. In these maps, the function M(x) is continuous and non-differentiable. Theoretical equations are found for the function M(x) and for the reinjection probability density function. Finally, the theoretical results are compared with numerical data finding high accuracy.

Este es un estudio numérico sobre la trayectoria del punto triple que se produce como resultado de la interacción de una onda de choque con velocidad variable sobre una superficie recta, lo que genera un proceso de reflexión inestacionario. La onda de choque cilíndrica se produce a partir de una súbita liberación de energía. Se comparan los resultados numéricos con resultados teóricos pseudoestacionarios y datos experimentales. Las simulaciones se desarrollan utilizando el esquema de Kurganov, Noelle y Petrova (KNP), mediante el Solver rhoCentralFoam del software OpenFOAM. Se observa una correlación apropiada de los resultados obtenidos con la simulación, alcanzándose una correcta descripción de la evolución del proceso y observándose diferencias en la trayectoria cuando x>3,5 m.