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S-Duct Inlet

Figure 1 is described in the surrounding text

Figure 1. Geometric configuration for subsonic flow in an s-duct inlet.

Problem Description

This case describes the computation of three-dimensional subsonic flow through an s-duct inlet. The inlet geometry (Test Case 3) was selected from the collection of inlet test cases provided by the AGARD Fluid Dynamics Panel Working Group 13 for validation of computational fluid dynamics codes for propulsion system inlet flows (AGARD-AR-270, 1991). The duct was assumed inviscid for Study #1 and viscous for Study #2 and Study #3. The effect of vortex generators is studied in Study #2 using the Wendt vortex generator model, whereas, Study #3 uses the BAY model.


The geometry consists of an inlet cowl, a constant area duct section and the s-duct itself. The constant area section is approximately one inlet duct diameter long and the s-duct portion is approximately three and one half inlet diameters long. The basic geometric configuration is shown in Figure 1.

Comparison Data

Experimental data from AGARD-AR-270, as well as an NPARC solution (see the S-Duct Example Case ) are used as data for comparison. An ASCII file containing the pressure distributions is in the file sductdata.txt.

Computational Studies

Table 1. Computational studies performed for the S-Duct inlet.
Study Category Person Comments
Study #1 Example J.C. Dudek One run. Inviscid.
Study #2 Example J.C. Dudek Viscous. Vortex Generator Model.
Study #3 Example J.C. Dudek Viscous. BAY Model.


"Air Intakes for High Speed Vehicles," AGARD-AR-270 (AGARD Advisory Report 270), Fluid Dynamics Panel Working Group 13, September, 1991.

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Last Updated: Monday, 02-Mar-2009 12:54:37 EST