Page 458 - Practical Design Ships and Floating Structures

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4 RESULTS
The flowfields around the underwater axisymmetric bodies with full appendages are computed as
steady-state solutions to the incompressible Navier-Stokes equations. The full appendages include a
fairwater and four stem appendages. The numerical velocity distribution and nominal wake at the
propeller are compared with the experiment data measured in the wind tunnel. The Reynolds number in
the calculation and experiment are 6.0~ IO6. The complete calculation was carried out by two steps.
The flowfields around the body and a fariwater are numerically simulated firstly, which can provide the
inlet boundary condition for the following fine simulation of flowfield around stem part of body and four
stem appendages.
The numerical dimensionless circumferential-mean velocity along the radius of the propeller are
presented in Fig. 1, which are in good agreement with the experimental data. The details of numerical
dimensionless circumferential-mean velocity and the experimental data can also been found in Table 1.
Except few points, the relative error between the numerical results and the experimental data is less than
3%, their average relative error is only 2.107%, the accurate numerical nominal wake at propeller can be
used as input data of vehicle propdsor blade design. The numerical dimensionless circumferential
velocity distribution at different radius station are showed in Fig. 2(a)-Fig. 2(g). There are difference
between the numerical results and the experimental data, but their phases are similar, so the calculated
circumferential velocity can be applied to the optimization and evaluation of hydrodynamics noise of
vehicle propulsor. The code developed in this paper has been used in the design and optimization of new
underwater bodies with full appendages.

TABLE 1
COMPARISON OF NUMERICAL CIRCUMFERENTIAL VELOCITY
WITH EXPERIMENTAL DATA

5 CONCLUSIONS

Based on flux-splitting, implicit high-resolution schemes have been constructed for efficient calculations
of steady-state solutions to the three dimensional, incompressible Navier-Stokes equations in curvilinear
coordinates. The third-order-accurate efficient EN0 has been applied in the calculations, which can
capture the details of the flowfield around underwater bodies with full appendages. The numerical
results agree quite well with the experimental data. The schemes and code developed in this paper can be
applied in the design of underwater vehicle propulsor and in the optimization and evaluation of its
hydrodynamics noise. Also the code can be used in the optimization and design of shapes of vehicle
body and its appendages.