Input
  • Examples from ESDU 00006
    • Section 7.1 Ex 1
    • Section 7.1 Ex 2
  • Examples from ESDU 00007
    • Section 7.2 Ex 1
    • Section 7.2 Ex 2
       with cavity depth = 1.2ft
  • Examples from ESDU 10016
    • Section 5.1.1 with Mach no = 0.8,
      cavity depth = 0.75ft, doors present
    • - blunt edges, no saw-tooth
    • - 15 deg chamfer, no saw-tooth
    • - 15 deg chamfer, 45 deg saw-tooth
    • - blunt edges, 45 deg saw-tooth
    • Section 5.1.1 with Mach no = 2.0,
      cavity depth = 0.75ft, doors present
    • - blunt edges, no saw-tooth
    • - 15 deg chamfer, no saw-tooth
    • - 15 deg chamfer, 45 deg saw-tooth
    • - blunt edges, 45 deg saw-tooth
  • DEBUG
    • As ESDU 00006 Section 7.1 Ex 1
       doors
    • Open flow regime
       no doors
    • Trans flow regime
       no doors, British units
  • Set as 1/m and other lengths as mm
  • Set as 1/m and other lengths as m
  • Set as 1/ft and other lengths as in
  • Set as 1/ft and other lengths as ft

Sketches and definitions

Summary

The program calculates the drag of a rectangular planform cavity, with or without doors, in a flat plate with a turbulent boundary layer for Mach numbers up to 3. The program follows the methods given in ESDU 00006 for closed flows and ESDU 00007 for open flows and transitional flows (see detailed description in ESDU 02008 for definitions of open, closed and transitional flows) for cavities without doors. The estimation of the effects of cavity doors on drag is made using the method given in ESDU 10016.

These Data Items should be consulted for full descriptions of the parameters, methods and their derivation. Section 5 of each Data Item discusses the accuracy and applicability of the methods. Those sections also detail the ranges for the geometric and flow parameters considered. The user is required to check that the ratio of cavity depth to boundary layer height is within the allowable range; however, the program is constrained to run only within the geometric and flow parameter ranges given in the various Figures within these Data Items. Outside those ranges no calculation will be performed but a simple error message will be displayed. The input parameters are described in Section 3 of ESDU 16007. Examples are provided for the worked examples in Section 7 of ESDU 00006 and 00007, and Section 5 of ESDU 10016.

ESDU 73017 and 77021 provide atmospheric data, if required. These Items are complemented by an associated Toolbox App.

ESDU 68020 provides data for a turbulent boundary layer on a flat plate, if required. Estimates for local and mean skin friction coefficients may be obtained from an associated Toolbox App.

General
Flow Conditions

At edge of boundary layer at cavity mid-length, in absence of cavity

Surface

At edge of boundary layer at cavity mid-length, in absence of cavity

Cavity
Results : Warning - the input has changed! Rerun the calculation contain errors or warnings
Save results as
Partial results are given below.

General

Cavity drag coefficient, including effect of doors (where present)

Intermediate calculations

Flow regime: 'closed'
Side-edge vortices

Flow regime: 'open'

Flow regime: 'transitional'

Effect of Doors

Note: with doors present cavity flow is assumed to be 2 dimensional

Subsonic/sonic flow:
{{tba.ep.o.esducalc.outputdata.cd_calculation.cavity_flowregime.doors.CDff.title}} 		{{occ.oodleCore.utils.valPrintPrecision(tba.ep.o.esducalc.outputdata.cd_calculation.cavity_flowregime.doors.CDff.value, 5)}}
Supersonic flow:
{{tba.ep.o.esducalc.outputdata.cd_calculation.cavity_flowregime.doors.CDwff.title}} 		{{occ.oodleCore.utils.valPrintPrecision(tba.ep.o.esducalc.outputdata.cd_calculation.cavity_flowregime.doors.CDwff.value, 5)}}
DEBUG
tba: 
{{tba | json}}

Loading...