Gateways to PHOENICS

Contents

  1. Purpose
  2. Method
  3. Gateways in preparation
  4. Relationship to 'special-purpose programs'
  5. Differences from conventional PHOENICS

1. Purpose

Gateways to PHOENICS have been designed so as to make it easy for persons who wish to simulate fluid flow in situations of narrowly-defined types to do so without:
  1. having their attention drawn to matters which do not concern them;
  2. needing to know anything about PHOENICS in general.


2. Method

Individual gateways are accessed by clicking one of the icons presented on the left of the main-gateway panel, whereupon further icons will appear which offer simulations of particular kinds.

Clicking on these will load the selected generic input file into an interactive software module called PRELUDE, which enables its user to:


3. What gateways are currently in preparation?

In various stages of completeness are:
  1. The 'Virtual Wind Tunnel', whether for:

  2. HVAC, i.e. Heating, Ventilating and Air-Conditioning, whereby users are enabled to furnish their rooms, concert halls or supermarkets with such items as:

  3. Fires and smoke-movement in buildings, for which, in addition to the objects which the HVAC specialist needs, the scenario is populated with:

  4. heat exchangers of various kinds, all based upon the use of volume-averaged parameters.

4. The relationship of 'gateways' to 'special-purpose programs'

4.1 A new form of an old idea

That special-purpose versions of PHOENICS should be provided for narrow-sector uses was a central feature of CHAM's thinking from the very beginning. Indeed, the word SATELLITE springs from the notion that the solver-module EARTH would be supplied with data from special-purpose satellites.

An early graphical representation of the concept can be seen below: [earth.gif]

Things did not work out quite as expected: there is now a single satellite; but CHAM sought to express the distinctions between applications areas by:

The task of creating, documenting, exemplifying and selling these distinct packages proved to be too great; and finally it was recognised as being unnecessary. In fact, there is ONE PHOENICS; and attempts to sub-divide it in accordance with application areas are pointless.

It is among the users that the differences lie which need to be respected; and each group, it is now recognised, requires a 'gateway to PHOENICS', designed to suit that group's special needs.

In designing a gateway therefore, CHAM seeks to:

Some examples will now be discussed.

4.2 The Virtual Wind Tunnel

  1. The starting scene of the virtual wind tunnel consists of:

  2. The store-cupboard of the virtual wind tunnel contains:

  3. The wizard of the virtual wind tunnel consists of the PRELUDE software module, with:
    1. its general capabilities of:
      • displaying the scene from various view-points;
      • moving, re-sizing, hiding, restoring to view, and changing attributes of, objects selected by the user;
      • removing objects from the scene;
      • bringing in objects from the store-cupboard or from any location specified by the user; and
      • defining relationships between positions and other data items,
    2. augmented by VWT-specific relations which, namely:
      • cause the wind-tunnel to change its size in proportion to that of the object;
      • enable the air-inlet velocity to be determined by reference to Reynolds number and/or Mach Number;
      • allow the 'angle of attack' of the object to be varied;
      • allow computer time to be spared, when object has a plane of symmetry, by simulating just one-half of the scene;
      • allow heat transfer to be included in the simulation; and
      • when the temperature does vary, to take the effect of buoyancy into account.

4.3 The Gateway to Heating, Ventilating and Air-Conditioning

  1. The starting scene of the HVAC Gateway consists of:

  • The store-cupboard of the HVAC Gateway contains:

  • The wizard of the HVAC Gateway consists of the PRELUDE software module, with:
    1. the same general capabilities as the Virtual Wind Tunnel wizard
    2. augmented by HVAC-specific relations which, namely:
      • enable the simulation to conducted in either steady state or transient mode;
      • enable the air-inlet rate from the diffuser to be varied in accordance with the temperature prevailing at a prescribed 'sensor' location;
      • allow the direction of flow of the fan to be varied cyclically with time;
      • enable groups of items (e.g. furniture, persons, heaters) to be re-positioned as a group;
      • allow the calculation of the distribution of various 'comfort indices'.


    5. Differences from conventional PHOENICS operation

    Persons who are familiar with PHOENICS may be interested to know that: CHAM's introduction of PRELUDE also expresses its new approach to the market-place.

    In the past, the developers of PHOENICS have furnished it with many valuable features, some of which are described in 'what's new' announcements or 'newsletters', and fewer of which have been illustrated in single-instance examples added to the input-file library. The developers may have then hoped that some salesman will convey the message to prospective custmers, who will thereby be persuaded to purchase the software.

    PRELUDE has been designed so as to enable CHAM itself to create the 'gateways' which are described in this document and of which the essential feature is their users require no knowledge of PHOENICS, or even of computational fluid dynamics.

    Were CHAM now to say to prospective customers: 'Here's PRELUDE. You can use it to make your own gateways', probably not one of them would be bold enough to accept.

    Television-set manufacturers provide ready-to-operate handsets, not tool-kits from which customers have to construct their own. So it must be with CHAM and the PHOENICS Gateways.