Boost logo

Boost Users :

Subject: Re: [Boost-users] units use and weird cases....suggestions needed
From: Matthias Schabel (boost_at_[hidden])
Date: 2009-09-09 01:18:06


> The problem domain is fluid dynamics so enter the Kv and Cv values.
>
> Technically these are a measure of volumetric flow. For instance,
> Kv is defined as:
>
> the flow of water with temperature ranging 5 - 30 oC through a valve
> in cubic meters per hour (m3/h) with a pressure drop of 1 bar
>
> The problem is that engineers see this as a "unitless" value and
> treat it as having no units at all. They use Kv in SI based
> equations, not m3/s as we'd expect. Thus all equations being fed to
> us use Kv as if it were a natural part of the equation.
>
> Most of the time these dimensions do not compute dimensionally
> anyway but there's rare cases when they do. I have gotten the
> engineers (those giving me specs for code I write) to decide on Kv
> instead of doing both Kv and Cv (it's a basic conversion).

It's a little hard to see where the problem is without a concrete
example. How about one equation and the corresponding function, with
ancillary information about the expected units of inputs/output?

Matthias


Boost-users list run by williamkempf at hotmail.com, kalb at libertysoft.com, bjorn.karlsson at readsoft.com, gregod at cs.rpi.edu, wekempf at cox.net