Flexcom > Data Inputs > $LOAD CASE

Purpose

To specify the composition of the downstream structure in terms of element sets for use in wake interference calculations. The keyword also facilitates the (optional) definition of lift coefficients in the case of a User-Defined wake interference model.

Theory

Refer to Wake Interference for further information on this feature.

Keyword Format

Blocks of lines defining the set(s) of elements which comprise the downstream structure, optionally an associated lift coefficient with each set, and optionally linking the downstream element set with a specific portion of the upstream structure.

A single line as follows. The line may be repeated as many times as necessary to completely define the downstream structure.

SET=Downstream Element Set Name [, LIFT=Lift Coefficient] [, UPSTREAM=Upstream Element Set Name]

Restrictions: The use of *WAKE DOWNSTREAM is compulsory if wake interference effects are to be included in an analysis. Downstream Element Set Name must be an existing element set, defined in the initial static analysis of the downstream structure. Lift Coefficient is a mandatory input in the case of a User-Defined wake interference model – otherwise it is irrelevant. Upstream Element Set Name must be an existing element set, defined in the initial static analysis of the upstream structure.

TABLE INPUT

Input:	Downstream Element Set Name	Lift Coefficient	Upstream Element Set Name
Description	The name of an existing set that contains the elements on the downstream structure that you want to include in the wake interference analysis. Can be specified as many times as required.	Mandatory lift coefficient in USER-Defined model. See note (a).	Optional name of an existing upstream element set. See note (b).

Notes

(a) Lift Coefficient is mandatory in a User-Defined model otherwise it is irrelevant.

(b)While the specification of an upstream element set is optional, if utilised correctly, it will improve the efficiency of the internal computations. Specifically, in determining the appropriate wake field for a downstream element, the program will first check a specific portion of the upstream structure (if specified) for a corresponding upstream element, before proceeding to checking the entire upstream structure if a suitable element is not found within the designated element set