Peter Vidmar | University of Ljubljana (original) (raw)

Papers by Peter Vidmar

The work includes an overview of road tunnel risk analysis methodologies that have been developed... more The work includes an overview of road tunnel risk analysis methodologies that have been developed in Europe as a consequence of several major accidents and subsequent Directive on minimum safety requirements for road tunnels. In our analysis, we used PIARC- OECD quantitative risk assessment model (QRAM), which includes the largest choice of different scenarios, tunnel types and traffic parameters. On the other hand, it does not include several risk reduction measures, which we managed to assess in our methodology by combining the QRAM with scenario based analysis in which we used 1D ventilation model, CFD fire model simulation and evacuation model. Apart from this, we present a calculation of risk acceptability criteria for Slovenia. There is also a description of risk assessment procedure and an example case study in which risk assessment of bidirectional and unidirectional traffic through a tunnel is carried out.

The idea behind the article is how to define fire behaviour. The work is based on an analytical s... more The idea behind the article is how to define fire behaviour. The work is based on an analytical study of fire origin, its development and spread. The study is based on thermodynamics, heat transfer and the study of hydrodynamics and combustion, which represent the bases of fire dynamics. The article shows a practical example of a leak of hazardous chemicals from a tank. Because of the inflammability of the fluid, fire may start. We have tried to model fire propagation around the Krško power plant, and show what extended surrounding area could be affected. The model also considers weather conditions, in particular wind speed and direction. For this purpose we have used the computer code Safer Trace, which is based on zone models. That means that phenomena are described by physical and empirical equations. An imperfection in this computer code is the inability to consider ground topology. However in the case of the Krško power plant, topology is not so important, as the plan is locate...

Risk is a common name for the probability of a hazard turning into a disaster. Vulnerability and ... more Risk is a common name for the probability of a hazard turning into a disaster. Vulnerability and hazard are not dangerous in and of themselves, but if they come together, they generate a risk. However, risk can be reduced and managed. If we are careful about how we treat the environment, and if we are aware of our weaknesses and vulnerabilities to existing hazards,

Thermal Science

Approaches to risk assessment in tunnelling and underground spaces were introduced in 2004 as a r... more Approaches to risk assessment in tunnelling and underground spaces were introduced in 2004 as a result of several serious accidents in tunnels such as Mont Blanc and Tauern Tunnel in 1999. The EU has published the minimum safety requirements for tunnels over 500 m on Trans-European Road Network. The risk assessment is mandatory and should cover all components of the system, i.e. infrastructure, operation, users and vehicles. The professional community has started using the QRA (Quantitative Risk Assessment) approach, where the crucial issue is the consequence analysis of fire scenarios in a tunnel. Fire development is a complex physical phenomenon and its calculation is time consuming; therefore, complex models have rarely been used in QRA approaches. This paper presents the methodology of integrating fast-processing risk assessment methods with time-consuming CFD (Computational Fluid Dynamics) methods for fire consequence analysis in the process of tunnel safety assessment. The mai...

The idea behind the article is how to define fire behaviour. The work is based on an analytical s... more The idea behind the article is how to define fire behaviour. The work is based on an analytical study of fire origin, its development and spread. The study is based on thermodynamics, heat transfer and the study of hydrodynamics and combustion, which represent the bases of fire dynamics. The article shows a practical example of a leak of hazardous chemicals from a tank. Because of the inflammability of the fluid, fire may start. We have tried to model fire propagation around the Krsko power plant, and show what extended surrounding area could be affected. The model also considers weather conditions, in particular wind speed and direction. For this purpose we have used the computer code Safer Trace, which is based on zone models. That means that phenomena are described by physical and empirical equations. An imperfection in this computer code is the inability to consider ground topology. However in the case of the Krsko power plant, topology is not so important, as the plan is locate...

The basic aim of this treatise is to research into relevant features of the multimodal transporta... more The basic aim of this treatise is to research into relevant features of the multimodal transportation chains, their advantages and disadvantages as well as the problems of the sinchronization of work of all participants in multimodal transport. With the development of information technology the method of optimisation of the multimodal transportation chains is more and more based on the computer programs being representative tools in solving of the comprehensive tasks. It is believed that the present research, the methodology applied and its findings, should promote and improve the multimodal transportation chains in order to cope with the complex contemporary logistic demands of global economy.

The paper presents the stages of creation of an autonomous historical navigational system simulat... more The paper presents the stages of creation of an autonomous historical navigational system simulator working both in real and accelerated time. The simulator allows performance of navigation tasks from the time of the ancient Vikings, as well as to fix a position by using the Decca system on a real Mk21 receiver recreated to cooperate with the artificial Decca system model. The Viking solar compass discovered on Wolin Island in 2013 was the trigger for creating such a simulator as part of a broader exhibition of navigational systems and tools. The main intention of the exhibition is to demonstrate the hyperbolic navigation application that links both systems.

This approach is based on the assumption that the ship hull can be represented as a non uniform s... more This approach is based on the assumption that the ship hull can be represented as a non uniform section beam. The propeller excitations in terms of pressure pulses and shaft line moments and forces are introduced. To take into account this exciting source in the early design stage a statistical formula for dynamic excitation of propeller was developed. Furthermore the superimposition of local effects has been performed with the use of an analytical formula. The local effect due to the different space topologies such as cabins, public spaces, technical and machinery areas has been taken into account. The transversal beams, longitudinal girders, stiffeners and pillars as supported structural elements are considered in the vibration local response.

The idea behind the article is how to define fire behaviour. The work is based on an analytical s... more The idea behind the article is how to define fire behaviour. The work is based on an analytical study of fire origin, its development and spread. Mathematical fire model called FDS (Fire Dynamic Simulator) is used in the presented work. A CFD (Computational Fluid Dynamic) model using LES (Large Eddie Simulation) is used to calculate fire development and spread of combustion products in the environment. The fire source is located in the vicinity of the hazardous plant, power, chemical etc. The article presents the brief background of the FDS computer program and the initial and boundary conditions used in the mathematical model. Results discuss output data and check the validity of results. The work also presents some corrections of the physical model used, which influence the quality of results. The obtained results were discussed and compared with the Fire Safety Analysis report included in the Probabilistic Safety Assessment of Krsko nuclear power plant.

Prispevek obravnava obnašanje požara oz. dimnega oblaka na odprtem prostoru. Prispevek temelji na... more Prispevek obravnava obnašanje požara oz. dimnega oblaka na odprtem prostoru. Prispevek temelji na analizi vira požara ter širjenja dimnega oblaka v okolico. Za simulacijo je uporabljen raèunalniški program FDS (Fire Dynamics Simulator). Model raèunske dinamike fluidov uporablja metodo simulacije velikih vrtincev za raèunanje dinamike gibanja zgorevalnih ostankov v okolici. Vir požara je postavljen v okolico nevarne zgradbe, v prispevku je predpostavljena okolica elektrarne Krško. Prispevek prikazuje kratko ozadje modela FDS ter zaèetne in robne pogoje, uporabljene pri modelu. Predstavljena je analiza izhodnih podatkov in predstavljana kakovost rezultatov. Prispevek podaja tudi nekatere popravke modela FDS, ki imajo pomemben vpliv na rezultate. © 2006 Strojniški vestnik. Vse pravice pridržane. (Kljuène besede: varnost protipožarna, analize varnostne, modeli, koncentracija dima, obmoèje nevarna)

Pedagogika-Pedagogy

The maritime safety is of great concern for the entire maritime community. Ships using LNG for pr... more The maritime safety is of great concern for the entire maritime community. Ships using LNG for propulsion are already sailing the seas, but the majority of the ports are not yet prepared for this kind of supply. As the process of LNG bunkering is only seemingly similar to traditional oil bunkering or liquid loading, dealing with the technical and safety challenges is much more subject of investigation. In this paper, the dispersion part of the consequences of LNG release, pooling, evaporation and dispersion during the future bunkering operation in the port of Koper, Slovenia, where the populated area (city) is located in close proximity are examined. We follow the comparison of three different tools, namely the Unified Dispersion Model (UDM) implemented by the software PHAST from DNV-GL® and two CFD (FDS – Fire Dynamics Simulator from NIST and Ansys Fluent®) in the same case scenario. Geometry, initial and boundary conditions are assumed to be the same as far as possible, according ...

Transactions on Maritime Science, Oct 21, 2018

Sustainable Maritime Transportation and Exploitation of Sea Resources, 2011

Sustainable Maritime Transportation and Exploitation of Sea Resources, 2011

The research explained in this paper was carried out to investigate the efficiency of different s... more The research explained in this paper was carried out to investigate the efficiency of different steering systems on sailing yachts. The steering system of a sail yacht mostly includes a simple steering system and a hydrodynamic shaped single rudder or multiple rudders, depending on boat characteristics. One of the basic design guidelines for fast sailing yachts is to reduce wetted surface to minimum allowed by the dynamic stability and maintaining the sailing performances. Deficiencies of different steering systems are discussed and their influences on total drag and yacht manoeuvrability in different sailing directions is analysed. The discussion is focused on steering systems applicable in practice and accepted by the yacht-building industry, although several innovations could be found that remained on their development stage because of their complexity in construction, maintenance, use itself and reliability. All measurements have been conducted at sea applying on board sensors for position and accelerations acquirements. The purpose of the research was to demonstrate that the use of the bended rudder can reduce the leeway angle, the upwind sailing angle and increase the velocity made good to windward.

Applied Sciences

Accidents in port areas are generally relatively minor given the lower prevailing speeds, but dan... more Accidents in port areas are generally relatively minor given the lower prevailing speeds, but dangerous cargo terminals located in the vicinity of populated areas present some risk of accidents with catastrophic consequences. The maritime risk assessment frameworks have been developed in many ports, but few include studies incorporating collisions between sailing and moored ships. This paper presents the risk assessment framework for such accidents. Moreover, it presents the important role of harbour regulations in the navigation risk management process within the port area. Today’s port regulations are created mostly based on the good practice of pilots and other experts, whereas quantitative methods are used less frequently. The intention of the presented case study was to demonstrate how quantitative risk assessment may be used in port policy development, which is why the method created is general and may be used in any terminal with dangerous cargo. The multi-stage method consis...

Journal of Marine Science and Engineering

The berthing of an ultra large ship is always a difficult issue and becomes yet more complex when... more The berthing of an ultra large ship is always a difficult issue and becomes yet more complex when vessels must be handled in restricted manoeuvring areas of limited depth, exposed to a forceful crosswind, or manoeuvring in a strong current, or all three. The final approaching manoeuvre and precise positioning is particularly demanding at container terminals where many STS cranes are located along the quay, seriously limiting margin for error in the process of mooring a ship, especially when the cranes are located nearby a bridge wing or at the very edge of the pier. In order to avoid collisions, the final manoeuvre (side-push) must be fully controlled; the ship’s orientation must be parallel with the quay while maintaining the minimum lateral approaching velocity without significantly shifting the vessel longitudinally. The mooring of a Ro-Ro vessel is occasionally even more challenging: a precise docking manoeuvre is normally executed without any towing assistance. In this paper lo...

The work includes an overview of road tunnel risk analysis methodologies that have been developed... more The work includes an overview of road tunnel risk analysis methodologies that have been developed in Europe as a consequence of several major accidents and subsequent Directive on minimum safety requirements for road tunnels. In our analysis, we used PIARC- OECD quantitative risk assessment model (QRAM), which includes the largest choice of different scenarios, tunnel types and traffic parameters. On the other hand, it does not include several risk reduction measures, which we managed to assess in our methodology by combining the QRAM with scenario based analysis in which we used 1D ventilation model, CFD fire model simulation and evacuation model. Apart from this, we present a calculation of risk acceptability criteria for Slovenia. There is also a description of risk assessment procedure and an example case study in which risk assessment of bidirectional and unidirectional traffic through a tunnel is carried out.

The idea behind the article is how to define fire behaviour. The work is based on an analytical s... more The idea behind the article is how to define fire behaviour. The work is based on an analytical study of fire origin, its development and spread. The study is based on thermodynamics, heat transfer and the study of hydrodynamics and combustion, which represent the bases of fire dynamics. The article shows a practical example of a leak of hazardous chemicals from a tank. Because of the inflammability of the fluid, fire may start. We have tried to model fire propagation around the Krško power plant, and show what extended surrounding area could be affected. The model also considers weather conditions, in particular wind speed and direction. For this purpose we have used the computer code Safer Trace, which is based on zone models. That means that phenomena are described by physical and empirical equations. An imperfection in this computer code is the inability to consider ground topology. However in the case of the Krško power plant, topology is not so important, as the plan is locate...

Risk is a common name for the probability of a hazard turning into a disaster. Vulnerability and ... more Risk is a common name for the probability of a hazard turning into a disaster. Vulnerability and hazard are not dangerous in and of themselves, but if they come together, they generate a risk. However, risk can be reduced and managed. If we are careful about how we treat the environment, and if we are aware of our weaknesses and vulnerabilities to existing hazards,

Thermal Science

Approaches to risk assessment in tunnelling and underground spaces were introduced in 2004 as a r... more Approaches to risk assessment in tunnelling and underground spaces were introduced in 2004 as a result of several serious accidents in tunnels such as Mont Blanc and Tauern Tunnel in 1999. The EU has published the minimum safety requirements for tunnels over 500 m on Trans-European Road Network. The risk assessment is mandatory and should cover all components of the system, i.e. infrastructure, operation, users and vehicles. The professional community has started using the QRA (Quantitative Risk Assessment) approach, where the crucial issue is the consequence analysis of fire scenarios in a tunnel. Fire development is a complex physical phenomenon and its calculation is time consuming; therefore, complex models have rarely been used in QRA approaches. This paper presents the methodology of integrating fast-processing risk assessment methods with time-consuming CFD (Computational Fluid Dynamics) methods for fire consequence analysis in the process of tunnel safety assessment. The mai...

The idea behind the article is how to define fire behaviour. The work is based on an analytical s... more The idea behind the article is how to define fire behaviour. The work is based on an analytical study of fire origin, its development and spread. The study is based on thermodynamics, heat transfer and the study of hydrodynamics and combustion, which represent the bases of fire dynamics. The article shows a practical example of a leak of hazardous chemicals from a tank. Because of the inflammability of the fluid, fire may start. We have tried to model fire propagation around the Krsko power plant, and show what extended surrounding area could be affected. The model also considers weather conditions, in particular wind speed and direction. For this purpose we have used the computer code Safer Trace, which is based on zone models. That means that phenomena are described by physical and empirical equations. An imperfection in this computer code is the inability to consider ground topology. However in the case of the Krsko power plant, topology is not so important, as the plan is locate...

The basic aim of this treatise is to research into relevant features of the multimodal transporta... more The basic aim of this treatise is to research into relevant features of the multimodal transportation chains, their advantages and disadvantages as well as the problems of the sinchronization of work of all participants in multimodal transport. With the development of information technology the method of optimisation of the multimodal transportation chains is more and more based on the computer programs being representative tools in solving of the comprehensive tasks. It is believed that the present research, the methodology applied and its findings, should promote and improve the multimodal transportation chains in order to cope with the complex contemporary logistic demands of global economy.

The paper presents the stages of creation of an autonomous historical navigational system simulat... more The paper presents the stages of creation of an autonomous historical navigational system simulator working both in real and accelerated time. The simulator allows performance of navigation tasks from the time of the ancient Vikings, as well as to fix a position by using the Decca system on a real Mk21 receiver recreated to cooperate with the artificial Decca system model. The Viking solar compass discovered on Wolin Island in 2013 was the trigger for creating such a simulator as part of a broader exhibition of navigational systems and tools. The main intention of the exhibition is to demonstrate the hyperbolic navigation application that links both systems.

This approach is based on the assumption that the ship hull can be represented as a non uniform s... more This approach is based on the assumption that the ship hull can be represented as a non uniform section beam. The propeller excitations in terms of pressure pulses and shaft line moments and forces are introduced. To take into account this exciting source in the early design stage a statistical formula for dynamic excitation of propeller was developed. Furthermore the superimposition of local effects has been performed with the use of an analytical formula. The local effect due to the different space topologies such as cabins, public spaces, technical and machinery areas has been taken into account. The transversal beams, longitudinal girders, stiffeners and pillars as supported structural elements are considered in the vibration local response.

The idea behind the article is how to define fire behaviour. The work is based on an analytical s... more The idea behind the article is how to define fire behaviour. The work is based on an analytical study of fire origin, its development and spread. Mathematical fire model called FDS (Fire Dynamic Simulator) is used in the presented work. A CFD (Computational Fluid Dynamic) model using LES (Large Eddie Simulation) is used to calculate fire development and spread of combustion products in the environment. The fire source is located in the vicinity of the hazardous plant, power, chemical etc. The article presents the brief background of the FDS computer program and the initial and boundary conditions used in the mathematical model. Results discuss output data and check the validity of results. The work also presents some corrections of the physical model used, which influence the quality of results. The obtained results were discussed and compared with the Fire Safety Analysis report included in the Probabilistic Safety Assessment of Krsko nuclear power plant.

Prispevek obravnava obnašanje požara oz. dimnega oblaka na odprtem prostoru. Prispevek temelji na... more Prispevek obravnava obnašanje požara oz. dimnega oblaka na odprtem prostoru. Prispevek temelji na analizi vira požara ter širjenja dimnega oblaka v okolico. Za simulacijo je uporabljen raèunalniški program FDS (Fire Dynamics Simulator). Model raèunske dinamike fluidov uporablja metodo simulacije velikih vrtincev za raèunanje dinamike gibanja zgorevalnih ostankov v okolici. Vir požara je postavljen v okolico nevarne zgradbe, v prispevku je predpostavljena okolica elektrarne Krško. Prispevek prikazuje kratko ozadje modela FDS ter zaèetne in robne pogoje, uporabljene pri modelu. Predstavljena je analiza izhodnih podatkov in predstavljana kakovost rezultatov. Prispevek podaja tudi nekatere popravke modela FDS, ki imajo pomemben vpliv na rezultate. © 2006 Strojniški vestnik. Vse pravice pridržane. (Kljuène besede: varnost protipožarna, analize varnostne, modeli, koncentracija dima, obmoèje nevarna)

Pedagogika-Pedagogy

The maritime safety is of great concern for the entire maritime community. Ships using LNG for pr... more The maritime safety is of great concern for the entire maritime community. Ships using LNG for propulsion are already sailing the seas, but the majority of the ports are not yet prepared for this kind of supply. As the process of LNG bunkering is only seemingly similar to traditional oil bunkering or liquid loading, dealing with the technical and safety challenges is much more subject of investigation. In this paper, the dispersion part of the consequences of LNG release, pooling, evaporation and dispersion during the future bunkering operation in the port of Koper, Slovenia, where the populated area (city) is located in close proximity are examined. We follow the comparison of three different tools, namely the Unified Dispersion Model (UDM) implemented by the software PHAST from DNV-GL® and two CFD (FDS – Fire Dynamics Simulator from NIST and Ansys Fluent®) in the same case scenario. Geometry, initial and boundary conditions are assumed to be the same as far as possible, according ...

Transactions on Maritime Science, Oct 21, 2018

Sustainable Maritime Transportation and Exploitation of Sea Resources, 2011

Sustainable Maritime Transportation and Exploitation of Sea Resources, 2011

The research explained in this paper was carried out to investigate the efficiency of different s... more The research explained in this paper was carried out to investigate the efficiency of different steering systems on sailing yachts. The steering system of a sail yacht mostly includes a simple steering system and a hydrodynamic shaped single rudder or multiple rudders, depending on boat characteristics. One of the basic design guidelines for fast sailing yachts is to reduce wetted surface to minimum allowed by the dynamic stability and maintaining the sailing performances. Deficiencies of different steering systems are discussed and their influences on total drag and yacht manoeuvrability in different sailing directions is analysed. The discussion is focused on steering systems applicable in practice and accepted by the yacht-building industry, although several innovations could be found that remained on their development stage because of their complexity in construction, maintenance, use itself and reliability. All measurements have been conducted at sea applying on board sensors for position and accelerations acquirements. The purpose of the research was to demonstrate that the use of the bended rudder can reduce the leeway angle, the upwind sailing angle and increase the velocity made good to windward.

Applied Sciences

Accidents in port areas are generally relatively minor given the lower prevailing speeds, but dan... more Accidents in port areas are generally relatively minor given the lower prevailing speeds, but dangerous cargo terminals located in the vicinity of populated areas present some risk of accidents with catastrophic consequences. The maritime risk assessment frameworks have been developed in many ports, but few include studies incorporating collisions between sailing and moored ships. This paper presents the risk assessment framework for such accidents. Moreover, it presents the important role of harbour regulations in the navigation risk management process within the port area. Today’s port regulations are created mostly based on the good practice of pilots and other experts, whereas quantitative methods are used less frequently. The intention of the presented case study was to demonstrate how quantitative risk assessment may be used in port policy development, which is why the method created is general and may be used in any terminal with dangerous cargo. The multi-stage method consis...

Journal of Marine Science and Engineering

The berthing of an ultra large ship is always a difficult issue and becomes yet more complex when... more The berthing of an ultra large ship is always a difficult issue and becomes yet more complex when vessels must be handled in restricted manoeuvring areas of limited depth, exposed to a forceful crosswind, or manoeuvring in a strong current, or all three. The final approaching manoeuvre and precise positioning is particularly demanding at container terminals where many STS cranes are located along the quay, seriously limiting margin for error in the process of mooring a ship, especially when the cranes are located nearby a bridge wing or at the very edge of the pier. In order to avoid collisions, the final manoeuvre (side-push) must be fully controlled; the ship’s orientation must be parallel with the quay while maintaining the minimum lateral approaching velocity without significantly shifting the vessel longitudinally. The mooring of a Ro-Ro vessel is occasionally even more challenging: a precise docking manoeuvre is normally executed without any towing assistance. In this paper lo...