A hydrodynamic model test device and method for additional mass of airship
An additional mass and hydrodynamic technology, applied in the field of measurement, can solve problems such as unobvious balance response, small force and moment measurement values, and lack of additional mass.
Active Publication Date: 2021-09-14
CHINA SPECIAL TYPE FLIER RES INST
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Problems solved by technology
The dynamic derivative test technology cannot meet the requirements of airship additional mass measurement, which is mainly reflected in the following aspects: (1) In this dynamic derivative test method, the dynamic derivative test method can only provide the three directions of pitch, roll and yaw; Motion, that is, the dynamic derivative test with the attitude angle of 0° in three directions, can only obtain the additional mass in the three rotational directions, and lacks the additional mass in the three translational directions
(2) The main technical difficulty is that the fluid medium attached to the aerostat is air, but the measured values of force and moment are very small, and the balance response is not obvious
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[0034] The principle of the test is as follows:
[0035] When the airship moves unsteadily in the ideal fluid, the magnitude of the aerodynamic force is proportional to the acceleration of the airship, and the direction is opposite to the direction of the acceleration, and its proportional constant is called the additional mass, expressed by λ ijexpress. The origin G of the airship is generally selected at the center of gravity of the boat; the x, y, and z directions are respectively the intersection lines of the horizontal plane, transverse section, and longitudinal mid-section passing through point G, and the forward direction is defined by the right-hand system, that is, the x direction points to the bow of the boat, and the y Direction pointing to starboard, z direction pointing up is positive. The additional mass always takes a positive value, and at the same time it is stipulated that the movement along the x, y, and z directions is represented by 1, 2, and 3; the rotat...
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The invention provides a hydrodynamic model test method for the additional mass of an airship, comprising: the hydrodynamic model 4 of the airship carries out forced sinusoidal periodic reciprocating motions in each direction of motion in the air respectively, and obtains the time elapsed force in each direction of motion in the air and torque; the forced sinusoidal periodic reciprocating motion in each direction of motion in water is obtained to obtain the elapsed force and moment in each direction of motion in the water; the elapsed force and moment in water are compared with the elapsed force and moment in air , corresponding to the subtraction, obtain the in-phase component and orthogonal component of the force and moment in each direction of the airship hydrodynamic model 4, and obtain the linear velocity derivative, angular velocity derivative, linear acceleration derivative and Angular acceleration derivative; invert the linear acceleration derivative or angular acceleration derivative of the airship hydrodynamic model 4 to obtain the additional mass in each motion direction; obtain the airship additional mass matrix according to the additional mass in each motion direction.
Description
technical field [0001] The invention relates to the field of measurement, in particular to a hydrodynamic model test device and method for additional mass of an airship. Background technique [0002] Additional mass means that when an object accelerates in the fluid, it causes the surrounding fluid to accelerate. Due to the inertia of the fluid, it is expressed as a reaction force on the object. The force pushing the object is greater than the inertial force of the object itself, which corresponds to greater than the inertia of the object itself. The mass of the force is the added mass. Compared with airplanes, airships have the characteristics of large volume and slow speed, and their inertial characteristics are very significant. According to the principles of fluid mechanics, the fluid inertia force must be considered, and the acquisition of additional mass is essential. The main way to get through the test is to carry out the forced vibration dynamic stability test in t...
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IPC IPC(8): G01M10/00
CPCG01M10/00
Inventor 史圣哲李徐郑小龙焦俊王丽丽李成华
Owner CHINA SPECIAL TYPE FLIER RES INST