Scalar transport near the surface of an immersed object will be handled with a cutcell method. Plans for FDS 7 include the ability to handle complex, unstructured geometry via a high-order immersed boundary method. The HVAC solver, a key addition to the model, was also included in version 6 and has been steadily enhanced. Since then gradual improvements have been made to hydrodynamics, chemistry, and multi-mesh calculations. FDS 6 was officially released in the fall of 2013. Over the next three years improvements were gradually added, and in 2010 work began on FDS 6, which began beta testing in the fall of 2012. It included a major overhaul of the input parameters and constructs. In short, better combustion and better pyrolysis. The work proceeded along two broad fronts - the gas phase and the solid phase. By 2005, it was clear that FDS was going to need a major overhaul, so we set about creating a new version (FDS 5) that would dramatically increase the flexibility and functionality of the model. Up to that point, FDS had been used by the FPE community for design applications, and to some extent forensic work, but the scope of the investigations pushed the model to its limits. Versions 3 (2002) and 4 (2004) saw gradual improvements in these routines, along with the introduction of parallel processing and various fire-specific features.ĭuring the NIST Investigations of the World Trade Center collapse and the Station Nightclub fire, it became fairly obvious what needed to be done with FDS to make it an effective tool for reconstructing fires. These improvements were implemented in version 2 (2001). Over the next few years, Jason Floyd, then a NIST post-doctoral fellow, and Simo Hostikka of VTT, Finland, as a guest researcher at NIST, developed the basic combustion model and the finite volume radiation transport solver, respectively. The first official version of FDS, released in 2000, was aimed at large scale simulations of smoke movement from prescribed, well-ventilated fires, ideal for design work where the fire's heat release rate is not predicted by the model, but rather specified by the designer or Authority Having Jurisdiction (AHJ). This addition improved the stability of the model because of the relatively simple relation between the local strain rate and the turbulent viscosity. To address this, we introduced the Smagorinsky model to close the LES subgrid stress in 1998. The early validation efforts were encouraging, but still pointed out the need to improve the hydrodynamic model. Much of the early work with this form of the model was devoted to the formulation of the low Mach number form of the Navier-Stokes equations and the development of the basic numerical algorithm.Įventually, the Boussinesq approximation was dropped and simulations began to include more fire-specific phenomena, such as fire plumes, ceiling jets, sprinkler activation, warehouse fires, and large oil fires. The early NIST LES model described the transport of smoke and hot gases in an enclosure using the Boussinesq approximation, where it is assumed that the density and temperature variations in the flow are relatively small. Before FDS, the various models were referred to as LES (large-eddy simulation), NIST-LES, LES3D, IFS (Industrial Fire Simulator), and ALOFT (A Large Outdoor Fire Plume Trajectory). In the mid 1990s, many of these different codes were consolidated into what eventually became FDS. However, for two decades prior to 2000, various CFD codes using the basic FDS hydrodynamic framework were developed at NIST by Howard Baum, Ron Rehm and Kevin McGrattan for different applications and for research. The Road TraveledįDS and Smokeview were officially released in 2000. I spend more time waiting for them to get in/out then actually unloading the trucks.This wiki describes research plans for enhancing the fire model FDS. (this is what the barcode system is meant for after all.)įinally one thing I dont understand - Why the hell are the delivery drivers getting out and standing by the trucks when they dont even unload the trucks? *the above I would really like to see put in soon, as late game its more of a headache trying to figure out what you have*Īs for down the road, a way to see what sells the most or perhaps even a way to implement 'stock ordering' so you can have a system that will track what you have sold and then you can choose to order just what you have sold and need again. I understand that you can 'see' whats on the shelf, but for some people its not an easy task to be able to tell from a glance. When ordering I would like to be able to see how many of the items I have currently 'in storage' so I don't double down on items - this way I always have stock of each available.Īlso save for when stocking shelves, show me how many of each are currently in the shelf.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |