Discussion:WUFI-Pro PerformanceandLimitations - Versionsgeschichte

Barbara: /* How to choose a suitable time step */

2009-03-10T11:12:53Z

How to choose a suitable time step

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	boundary conditions are assumed to be constant. For example, if you have hourly mean values		boundary conditions are assumed to be constant. For example, if you have hourly mean values
	of the weather data, a time step of one hour is sufficient - smaller time steps do not		of the weather data, a time step of one hour is sufficient - smaller time steps do not
	increase accuracy. ~~[##Update: numerical advantages##]~~		increase accuracy.
	</P>		</P>
	<P>		<P>

2009-03-10T11:09:35Z

How to choose a suitable time step

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	</P>		</P>
	<P>		<P>
	The explicit scheme is the simplest one ~~[##update: calculated one by one##]~~. However, its		The explicit scheme is the simplest one. However, its
	stability reqires that the width of the time step is below some upper limit which		stability reqires that the width of the time step is below some upper limit which
	depends on the spatial discretisation. A high spatial resolution thus requires very		depends on the spatial discretisation. A high spatial resolution thus requires very

2009-03-10T11:06:51Z

How to choose a suitable numerical grid

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	[[1D:Dialog_Numerics \| stricter numerical parameters]] (convergence failures		[[1D:Dialog_Numerics \| stricter numerical parameters]] (convergence failures
	are also discussed in the [[FAQ:WUFI-1D \| "Questions		are also discussed in the [[FAQ:WUFI-1D \| "Questions
	and Answers"]] section). ~~[##update Schrittweitensteuerung##]~~		and Answers"]] section).
	</P>		</P>
	<P>Unfortunately, there are presently no common methods which can reliably recognise		<P>Unfortunately, there are presently no common methods which can reliably recognise

2009-03-10T11:04:06Z

How to choose a suitable numerical grid

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	<P>		<P>
	This compliance with a basic physical principle means that even coarse, wide-meshed grids		This compliance with a basic physical principle means that even coarse, wide-meshed grids
	can be expected to give physically realistic ~~[##update kaum physikalisch völlig sinnlose Ergebnisse##]~~ results.		can be expected to give physically realistic results.
	</P>		</P>

2009-03-10T10:41:41Z

Numerical Problems

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	as to be able to automatically and perfectly adapt themselves to every problem. So it's		as to be able to automatically and perfectly adapt themselves to every problem. So it's
	up to you, the user, to do part of the work that ideally should be done by the computer		up to you, the user, to do part of the work that ideally should be done by the computer
	itself: you have to define a numerical grid ~~[##HREF##]~~ and to choose a suitable time step ~~[##HREF##]~~.		itself: you have to define a numerical grid and to choose a suitable time step.
	</P>		</P>

2009-03-10T10:36:33Z

Input Errors

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	interpretation of the [[Details:Material \| material data]], [[Details:Surface \| surface transfer coefficients]] etc.		interpretation of the [[Details:Material \| material data]], [[Details:Surface \| surface transfer coefficients]] etc.
	is the same as yours.<BR>		is the same as yours.<BR>
	Note there are possible ##side effects if you are		Note there are possible side effects if you are
	[[Glossary:Glossary-1D \| generating]] tables from standard data.		[[Glossary:Glossary-1D \| generating]] tables from standard data.
	</P>		</P>

2008-10-02T07:43:19Z

Limitations of the Mathematical Model

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	For simplicity, the [[Details:HeatTransfer \| heat transfer coefficients]]		For simplicity, the [[Details:HeatTransfer \| heat transfer coefficients]]
	are treated as constant or exhibiting a simple predefined dependence on wind speed. Regarding the simplified longwave radiation exchange with the surroundings, see		are treated as constant or exhibiting a simple predefined dependence on wind speed. Regarding the simplified longwave radiation exchange with the surroundings, see
	[[Details:~~Longwave~~ \| Reference: Long-wave Radiation Exchange]].		[[Details:LongWaveExchange \| Reference: Long-wave Radiation Exchange]].
	</P>		</P>
	<P>		<P>

2008-10-02T07:42:50Z

Limitations of the Mathematical Model

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	<P>		<P>
	Several transport phenomena have been neglected (cf.		Several transport phenomena have been neglected (cf.
	[[1D:~~WUFI_1D_What_is~~ \| "What is WUFI?"]]), that is why e.g. air flows in		[[1D:Wufi_1D_What is \| "What is WUFI?"]]), that is why e.g. air flows in
	the component, uptake of ground water under hydrostatic pressure etc. cannot be		the component, uptake of ground water under hydrostatic pressure etc. cannot be
	calculated.		calculated.

2008-10-02T07:42:18Z

Limitations of the Mathematical Model

← Nächstältere Version		Version vom 2. Oktober 2008, 09:42 Uhr
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	<P>		<P>
	Several transport phenomena have been neglected (cf.		Several transport phenomena have been neglected (cf.
	[[1D:~~WUFI_1D_Whatis~~ \| "What is WUFI?"]]), that is why e.g. air flows in		[[1D:WUFI_1D_What_is \| "What is WUFI?"]]), that is why e.g. air flows in
	the component, uptake of ground water under hydrostatic pressure etc. cannot be		the component, uptake of ground water under hydrostatic pressure etc. cannot be
	calculated.		calculated.

2008-10-02T07:42:07Z

Limitations of the Mathematical Model

← Nächstältere Version		Version vom 2. Oktober 2008, 09:42 Uhr
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	<P>		<P>
	Several transport phenomena have been neglected (cf.		Several transport phenomena have been neglected (cf.
	[[1D:~~WUFI_1D_WhatIs~~ \| "What is WUFI?"]]), that is why e.g. air flows in		[[1D:WUFI_1D_Whatis \| "What is WUFI?"]]), that is why e.g. air flows in
	the component, uptake of ground water under hydrostatic pressure etc. cannot be		the component, uptake of ground water under hydrostatic pressure etc. cannot be
	calculated.		calculated.