Method and device for reducing wave-making resistance and friction force during ship navigation

A method for reducing wave-making resistance and friction force during ship navigation, the method comprising:

• injecting, an air-water mixture containing bubbles that is generated by a device, into water areas in front of a ship or/and on both sides of the ship;
• wherein, in the air-water mixture, a volume ratio of air is 10% to 60%,
• wherein the device generating the air-water mixture containing bubbles comprises:
• a gas-liquid mixing device, provided with a water inlet, a gas inlet and a water outlet, wherein the gas-liquid mixing device is further provided with a gas-liquid mixing cavity between the water inlet and the water outlet, water enters the gas-liquid mixing cavity via the water inlet, and gas enters the gas-liquid mixing cavity via the gas inlet;
• and
• a control device, which is connected to the gas-liquid mixing device, and controls continuous low-speed water intake, or intermittent suspension of water intake, or cyclic switching between high-speed water intake and low-speed water intake at the water inlet during the gas intake at the gas inlet;
• wherein the water entering the gas-liquid mixing cavity is mixed with air to form the air-water mixture containing bubbles, and the air-water mixture is discharged via the water outlet;
• the water intake is suspended at the water inlet each time for 1 second to 9 seconds;
• or, when the low-speed water intake is intermittent at the water inlet, a time for the low-speed water intake each time is 1 second to 9 seconds.