CEHIPAR

Presentation

El Pardo Campus, dependent of INTA-SGSN, is located in the facilities of the former “Canal de Experiencias Hidrodinámicas de El Pardo” (El Pardo model basin), created in 1928 by the Spanish Navy. INTA-SGSN has facilities and services dedicated to research and experimentation in the field of hydrodynamics, and offers its commercial services to companies, military and civil, mainly in the field of shipbuilding.

In July 2017, El Pardo Campus of INTA was recognized by the Spanish Ministry of Economy and Competitiveness (MINECO) as Singular Scientific and Technical Infrastructure (ICTS), under the name of “El Pardo Hydrodynamic Experiences Center” (CEHIPAR).

The work carried out contributes decisively to more cost-efficient running of vessels and their greater safety through optimization of hull resistance and propulsive efficiency as well as improving seaworthiness and reducing movements at sea. Studies into safety under extreme conditions are also carried out.

ICTS-CEHIPAR has responded to the ever greater industrial demands on it by building and rolling out new facilities and constantly renovating the existing ones. Its facilities are furnished with state-of-the-art instrumentation.

Its ongoing research and innovation activities in collaboration with universities, research institutes and companies from Spain and other countries have given ICTS-CEHIPAR the necessary expertise to act as a competent partner in developing science and services for new market strategies.

At present, its software and data bases, covering over 24 000 tests, and its experienced personnel, allow it to draw up designs, evaluations and simulations rapidly and reliably.

FACILITIES

Ship Dynamics Laboratory (Physical Scale Laboratory ICTS-I3a-3)

The Ship Dynamics laboratory provides the latest technology for wave generation and test instruments and devices for measuring the movements of ships and other floating structures in the presence of waves and wind.

Specifications

Basin

  • Length: 150 m
  • Width: 30 m
  • Depth: 5 m + sectional pit (10 x 10 m) of 5 m additional depth, thus achieving total depth of 10 m.

C.P.M.C. (Computerized Planar Motion Carriage)

The CPMC is a set of moving structures above the surface of the tank. It consists of a principal carriage and sub-carriages. Its basic objective is high-precision reproduction of all possible horizontal movements of a ship or any floating structure at sea.

The principal carriage can be moved uniformly and horizontally along the tank. The three sub-carriages hang below the principle one and are mechanically independent and permit transverse, incremental and rotational motions that are superposed onto the movement of the principle carriage.

The transversal sub-carriage can vary the vertical position of the incremental and rotational sub-carriages, thus adjusting the conditions required for the tests.

The CPMC self-developed software automatically controls the movements of the carriages, their positioning, the position of the model, acquisition of data, evaluation of the test runs, etc.

Wave generator

Multiflap snake-effect generator. Its total width is 30 m and it has 60 articulated rigid flaps, with hinges located 2 m from the bottom of the channel. The segments or flaps that set up the wave generator are hydraulically operated independently. A wave absorber beach is mounted on the opposite side.

Types of waves generated: longitudinal and oblique regular waves of lengths between 1 and 15 m and heights up to 0.9 m. Oblique waves ±45º, long and short-crested irregular waves of significant heights up to 0.4 m, standard and arbitrary spectra, capacity to reproduce group spectra and episodic waves.

Wind generator

Capacity of simulating the aerodynamic loads on the vessel or the marine structure by means of fans installed on the models.

Calm Water Towing Tank (Physical Scale Laboratory ICTS-I3a-1)

The Calm Water Towing Tank is the facility where the hydrodynamic characteristics of ships and propellers without waves are studied.

Specifications

Basin

Dimensions: 320 m long, 12.5 m wide and 6.5 m deep.

Towing carriage

Speeds up to 10 m/s.

Maximum acceleration 1 m/s².

Control software that automatically establishes the velocity profile of the tests.

Equipment

Among the wide variety of instrumentation available the following equipment should be mentioned:

  • Towing dynamometer.
  • Propeller dynamometer.
  • Dynamometers for propulsion tests.
  • Six-component dynamometer.
  • Video cameras and recording equipment.
  • Particle Image Velocimeter (PIV).

It also has a digital data acquisition system which collects model test data automatically and a computer program for the analysis and presentation of results, specifically developed for this facility. The modernization of this facility continues. 

Cavitation Tunnel (Physical Scale Laboratory ICTS-I3a-2)

A cavitation tunnel is available at the INTA-CEHIPAR. Tests and research are performed with conventional, controllable pitch propeller, contra-rotating propellers, ducted propeller and all types of unconventional propellers as CLT, Tip rake. Test uniform or variable flows maybe performed with the possibility of inclination of the shaft line.

The tunnel is suitable for propeller models with a maximum diameter of 450 mm. Maximum water speed is 11 m/s in the test section. Cavitation index may be varied from 0.32 to 130.

The wake field can be reproduced in the tunnel by mean of meshes as well as by introducing a dummy model in the test section. A CRP-POD propulsion system installed in a dummy model were tested at the cavitation tunnel for the TRIPOD research supported by EU.

Inception test are carried out in order to determine the type of cavitation as a relation of the advanced ratio with different cavitation numbers.

To carry out the measurements of the nominal and effective wakes distributions a Laser Doppler Anemometer is available with the possibility to distinguish two velocity components on disturbing the flow.

Erosion test are carried out to evaluated the damage due to cavitation in marine propellers.

Pressure pulses measurement tests may be carried out by using pressure transducers and Hottinger equipment to process the signal are used.

Maneuverability in open lake (Field Laboratory ICTS-I3b)

Maneuverability expresses the movements of the ship in a horizontal plane under calm water conditions. The maneuverability data is used for the design of the control surfaces, mainly the rudder. Variations of the control surfaces affect the course stability, the ability to run away in certain emergency situations, turning ability, turning radius for some kinds of fishing operations, the necessary stopping distance.

Free-running model maneuvering are done with a ship model, fitted out with the necessary instrumentation, tested in inshore waters. The model is guided by a remote control and is self-propelled and controlled. Valmayor reservoir, not far from Madrid and with enough water surface and depth for maneuvering without danger of collision, is used.

The organization has the knowledge, equipment and instrumentation necessary to perform and analyze free-running model maneuverability tests. The main maneuvers are: turning circle, pull-out, zig-zag, spiral and crash stop.

These maneuverability tests complement the maneuvers with captive model in which the model with its instrumentation is fixed through dynamometers to the computerized planar motion carriage (CPMC) of the Ship Dynamics Laboratory. 

Numerical Hydrodynamics, CFD (Numerical Modeling ICTS-I3c)

Projects of hull shapes and propellers, and their optimization before model tests in the towing tank, are done by means of numerical simulations or CFD (Computational Fluid Dynamics).

Flow around the hull for a velocity is optimized with CFD tools. Flow main characteristics as generated wave patterns, pressure and velocity fields, streamlines and resistance coefficients are obtained after computation.

Propellers are designed with specialized CFD software to calculate steady and unsteady forces, cavitation type, harmonics and pressure pulses in the stern.

Characteristics:

  • Hull shapes:

Generalist CFD codes as ANSYS FLUENT, ANSYS CFX and OpenFOAM are the main tools used to study and modify hull shapes.

  • Propellers:

Propellers’ performance is computed with the same generalist CFD codes used for hull shapes and some specific tools based on VLM lifting surface method. It is possible to compute sheet cavitation and wake alignment, adding viscosity, tip vortex and boundaries corrections. Hull-propeller interaction can be computed with low order panels and image methods.

Results:

The main numerical and graphical results are:

·       Hull shapes:
  • Pressure and velocity fields on hull surface and water free surface.
  • Wave pattern.
  • Wave profile.
  • Limiting streamlines.
  • Friction coefficient distribution.
  • Boundary layer thickness.
  • Lifting forces in lifting surfaces.
·       Propellers:
  • Main propeller curves and efficiency for different open water conditions.
  • Thrust, power and propeller efficiency for a specific condition after the ship.
  • Forces and torques pulses (6 components) on every blade and the shaft.
  • Sheet cavitation performance in several blade positions
  • Harmonics of the cavity volume change.
  • Pressure distribution on the blades.
  • Pressure pulses in the ship stern.