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A method and apparatus for determining small magnitude fluid-dynamic drag resistance differentials between different structural configurations of a variable model mounted in an environmental test facility. The variable model has disposed therein a configuration conversion mechanism to convert the va

A method and apparatus for determining small magnitude fluid-dynamic drag resistance differentials between different structural configurations of a variable model mounted in an environmental test facility. The variable model has disposed therein a configuration conversion mechanism to convert the variable model from a baseline configuration to a modified baseline configuration, i.e., the baseline configuration with a minor structural modification superimposed thereon, and vice versa, a nulling force mechanism to apply a nulling force to the variable model to null out the total fluid-dynamic drag resistance acting thereon, i.e., return the variable model to an undeflected position, and a system for measuring the deflections of the variable model caused by the small magnitude fluid-dynamic drag resistance differentials acting thereon. The variable model is mounted in the environmental test facility, and a predetermined fluid flow is initialized and stabilized. An initial deflection of the variable model due to the total fluid-dynamic drag resistance acting thereon is nulled out by applying the nulling force to the variable model through the nulling force mechanism. The variable model is then alternately converted to the baseline configuration and the modified baseline configuration by remote actuation of the configuration conversion mechanism, and the small magnitude fluid-dynamic drag resistance differentials acting thereon are determined by measuring the deflections of the variable model by the measuring system. The efficacy of the minor structural modification to the variable model may then be assessed by comparing the small magnitude fluid-dynamic drag resistance differentials of the different configurations.

대표청구항 ▼

An apparatus for determining small magnitude fluid-dynamic drag resistance differentials acting on a variable model mounted in an environmental test facility, said environmental test facility including means for mounting said variable model therein, comprising: a configuration conversion mechanism d

An apparatus for determining small magnitude fluid-dynamic drag resistance differentials acting on a variable model mounted in an environmental test facility, said environmental test facility including means for mounting said variable model therein, comprising: a configuration conversion mechanism disposed within said variable model and cooperating therewith to alternately convert said variable model to a baseline configuration and a modified baseline configuration; a nulling force mechanism disposed within said variable model and cooperating with said variable model and said mounting means to be selectively apply a nulling force to said variable model to null out a total fluid-dynamic drag resistance acting on said variable model due to a predetermined fluid flow in said environmental test facility such that said variable model is returned to an undeflected position; and means for measuring deflections of said variable model caused by said small magnitude fluid-dynamic drag resistance differentials acting thereon, said measuring means being disposed within said variable model and cooperating with said variable model and said mounting means, whereby after said predetermined fluid flow is initialized and stabilized in said environmental tunnel and said nulling force is applied to said variable model by said nulling force mechanism to return said variable model to said undeflected position, said variable model is alternately converted to said baseline configuration and said modified baseline configuration and said small magnitude fluid dynamic drag resistance differentials acting thereon to cause deflections of said variable model are measured by said deflection measuring means.