Dynamic computer modeling of environmental systems for decision making, risk assessment and design

Markatos, N.C.

doi:10.1002/apj.654

Cited by 10 publications

(3 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The k and ω transport equations are solved simultaneously with the three momentum Navier-Stokes equations together with the continuity and energy equations, a total of 7 differential equations. This set of equations is solved using the finite-volume technique, details of which may be found in literature [20,[41][42][43]. More specifically, the equations are transformed to curvilinear body-fitted-coordinate form and are solved as in Galea and Markatos [44] and in Spyridakos, et al [45].…”

Section: { }mentioning

confidence: 99%

Mathematical Modelling and Comparative Numerical Simulations of Swing-Fuselage Junction Vortex Structures

S¹,

NC²

2022

J Aerosp Eng Mech

View full text Add to dashboard Cite

Turbulence and flow disturbances occurring at the aircraft wing-fuselage junction cause a deterioration of its aerodynamic performance and an increase in the aircraft's drag force. However, the aircraft junction regions are currently designed empirically due to the lack of knowledge of detailed junction flow dynamics, which consequently leads to less efficient flow management and poorer aerodynamic characteristics. The main objective of the present mathematical-modelling study is research on an aerodynamically enhanced design approach, concerning the improvement of the characteristics of the junction flow and its vortices. Numerical simulations are performed under the prism of vortices' structure formation and patterns, particularly of the horseshoe and corner separation vortices, which dominate such flows. More specifically, this research study proposes a new junction flow parameter, which has been employed in combination with the existing ones, in order to result in a more streamlined and efficient junction design, and investigates the junction flow response, when the reference junction design of a wing-fuselage system is modified by the addition of "fillet", "strake" and "blending" geometry types on the wing. Flow simulations are performed in steady-state mode, at transonic flight regime and at 2° angle of attack, using two turbulence models: The Reynolds Averaged Navier-Stokes (RANS) SST k-ω turbulence model, enhanced with rotation/curvature corrections (SST-CC) and with eddy viscosity and turbulence production limiters, and the second-order closure Reynolds Stress model. The geometrical modifications that were implemented proved to be efficient and their application in the design process of modern aircraft foreshadows the possibility of achieving enhancedperformance flights. More specifically, all the three modifications of the reference geometry increased the aircraft's aerodynamic efficiency, by improving the flow pattern around the wing-fuselage regions at the studied flight state. The most promising configuration proved to be the one which combined the "fillet" and "strake" geometries, resulting in the highest aerodynamic efficiency, by greatly weakening the horseshoe vortex and eliminating the corner separation.

show abstract

Section: { }mentioning

confidence: 99%

Mathematical Modelling and Comparative Numerical Simulations of Swing-Fuselage Junction Vortex Structures

S¹,

NC²

2022

J Aerosp Eng Mech

View full text Add to dashboard Cite

show abstract

“…The prediction of the dispersion of a hazardous pollutant is a difficult, because depends on complex physical phenomena and, contains lot of uncertainty on the determined results. The constrained open space of urban geometries obstructs the hazardous materials, favouring the mass trap inside the city's environment [1]. The accidental risk analysis techniques, define the systematic hazards identification, record the accidental causes and determine the protection measurements [2].…”

Section: Introductionmentioning

confidence: 99%

Assessment of air flow distribution and hazardous release dispersion around a single obstacle using Reynolds-averaged Navier-Stokes equations

Vasilopoulos

Sarris

Tsoutsanis

2019

Heliyon

View full text Add to dashboard Cite

The flow around a cubical building, with a pollution source at the central point of the top of the cube, is studied. The Reynolds-averaged Navier-Stokes and species concentration equations are solved for Reynolds number, Re = 40,000, is based on the height of the cube. The predictions obtained with the standard, the Kato-Launder, and the low-Reynolds number k-epsilon models are examined with various wall functions for the near wall treatment of the flow. Results are compared against Martinuzzi and Tropea measurements (J. of Fluids Eng., 115, 85–92, 1993) for the flow field and against Li and Meroney (J. of Wind Eng. and Industrial Aerodynamics, 81, 333–345, 1983) experiments and Gaussian models for the concentration distribution. It is found that the present unstructured mesh model performs similarly to the structured mesh models. Results from the Kato-Launder model are closer to the experimental data for the flow patterns and contaminant distribution on the cube's roof. However, the Kato-Launder model has an over-prediction for the recirculation zone and the contaminant distribution windward of the cube. The standard k-epsilon and the low-Reynolds number k-epsilon models predict similar flow patterns and are closer to the experimental data of the cube's windward and side face.

show abstract

“…Markatos et al deduced that the production of combustion products and smoke caused environmental problems and health issues over the whole plant and the concentration of toxic substance should be estimated. In another study conducted by Markatos et al [18], the toxic combustion products after a pool fire was modeled using CFD simulation. The results of simulations were used to determine risk zones on the facility.…”

Section: Introductionmentioning

confidence: 99%

Integrated Consequence Modelling for Fire Radiation and Combustion Product Toxicity in offshore Petroleum Platform using Risk Based Approach

et al. 2018

View full text Add to dashboard Cite

The processing area of offshore platform has high probability of leakage of hydrocarbons. Liquefied Natural Gas (LNG) is one of the most common hydrocarbon produced in offshore platforms. Leakage of LNG can cause pool fire, jet fire, flash fire or fire ball. Thermal radiations due to fire is the major source of damage to workers on board. But due to fire, various combustion product toxic gases are also produced that have both acute and chronic health effects. These toxic gases can cause incapacitation, increased heart rate, vomiting and even death. Predicting the human injury due to thermal radiations and concentration of toxic gases are the key issues. A risk based approach takes in to consideration the duration a worker spent on different location of offshore platform and also it has the additive ability to evaluate overall risk due to fire radiation and toxic gases. Grid based approach helps in better visualization of risk posed by fire radiation and combustion product toxic gases at different locations of platform. The current study proposed an integrated consequence modelling approach for fire and combustion product toxic gases using risk based and grid based approaches. The integrated accident is modelled using Computational Fluid Dynamics (CFD) code Fire Dynamics Simulator (FDS). The results showed that risk posed by thermal radiation is confined on sub cellar deck (lower deck) but estimated risk due to combustion product gas (carbon monoxide) on cellar deck (upper deck) has significant value that needs to be considered. The current approach would be useful for emergency preparedness plans and safety measures designs for offshore platforms.

show abstract

Dynamic computer modeling of environmental systems for decision making, risk assessment and design

Cited by 10 publications

References 48 publications

Mathematical Modelling and Comparative Numerical Simulations of Swing-Fuselage Junction Vortex Structures

Mathematical Modelling and Comparative Numerical Simulations of Swing-Fuselage Junction Vortex Structures

Assessment of air flow distribution and hazardous release dispersion around a single obstacle using Reynolds-averaged Navier-Stokes equations

Integrated Consequence Modelling for Fire Radiation and Combustion Product Toxicity in offshore Petroleum Platform using Risk Based Approach

Contact Info

Product

Resources

About